build-system: Use 'sexp->gexp' for plain sexps.

This reduces memory allocations and list traversals during 'gexp->sexp',
'gexp-inputs', etc.

* guix/build-system/cargo.scm (cargo-build): Use 'sexp->gexp' for sexps
known to not contain file-like objects.  Change default #:phases to a
symbol.
* guix/build-system/cmake.scm (cmake-build, cmake-cross-build): Likewise.
* guix/build-system/copy.scm (copy-build): Likewise.
* guix/build-system/font.scm (font-build): Likewise.
* guix/build-system/glib-or-gtk.scm (glib-or-gtk-build): Likewise.
* guix/build-system/gnu.scm (%strip-flags, %strip-directories): New
variables.
(gnu-build): Use them.  Use 'sexp->gexp' where appropriate.
(gnu-cross-build): Likewise.
* guix/build-system/meson.scm (meson-build): Likewise.
* guix/build-system/perl.scm (perl-build): Likewise.
* guix/build-system/python.scm (python-build): Likewise.
* guix/build-system/ruby.scm (ruby-build): Likewise.
* guix/build-system/scons.scm (scons-build): Likewise.
* guix/build-system/texlive.scm (texlive-build): Likewise.
* guix/build-system/trivial.scm (trivial-build): Likewise.
* guix/build-system/waf.scm (waf-build): Likewise.
* guix/build-system/android-ndk.scm (android-ndk-build): Likewise.
* guix/build-system/ant.scm (ant-build): Likewise.
* guix/build-system/asdf.scm (asdf-build/source, asdf-build): Likewise.
* guix/build-system/chicken.scm (chicken-build): Likewise.
* guix/build-system/clojure.scm (clojure-build): Likewise.
(source->output-path, maybe-guile->guile): Remove.
* guix/build-system/dub.scm (dub-build): Likewise.
* guix/build-system/emacs.scm (emacs-build): Likewise.
* guix/build-system/go.scm (go-build): Likewise.
* guix/build-system/haskell.scm (haskell-build): Likewise.
* guix/build-system/julia.scm (julia-build): Likewise.
* guix/build-system/linux-module.scm (linux-module-build)
(linux-module-build-cross): Likewise.
* guix/build-system/maven.scm (maven-build): Likewise.
* guix/build-system/minify.scm (minify-build): Likewise.
* guix/build-system/node.scm (node-build): Likewise.
* guix/build-system/qt.scm (qt-build, qt-cross-build): Likewise.
* guix/build-system/r.scm (r-build): Likewise.
* guix/build-system/rakudo.scm (rakudo-build): Likewise.
* guix/build-system/renpy.scm (renpy-build): Likewise.
* guix/packages.scm (patch-and-repack): Use 'sexp->gexp' when SNIPPET is
a pair.
* guix/svn-download.scm (svn-multi-fetch): Use 'sexp->gexp' for
'svn-multi-reference-locations'.

34 files changed, 278 insertions, 232 deletions

diff --git a/guix/build-system/android-ndk.scm b/guix/build-system/android-ndk.scm
index d8896e2305..fa8b1e2f12 100644
--- a/guix/build-system/android-ndk.scm
+++ b/guix/build-system/android-ndk.scm
@@ -41,8 +41,7 @@
                             source
                             (tests? #t)
                             (test-target #f)
-                            (phases '(@ (guix build android-ndk-build-system)
-                                        %standard-phases))
+                            (phases '%standard-phases)
                             (outputs '("out"))
                             (make-flags #~'())
                             (search-paths '())
@@ -55,7 +54,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (android-ndk-build #:name #$name
                              #:source #+source
@@ -70,8 +69,9 @@
                                                    "/share/android/build/core/main.mk")
                                     #$make-flags)
                              #:outputs #$(outputs->gexp outputs)
-                             #:search-paths '#$(map search-path-specification->sexp
-                                                    search-paths)
+                             #:search-paths '#$(sexp->gexp
+                                                (map search-path-specification->sexp
+                                                     search-paths))
                              #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad  ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/ant.scm b/guix/build-system/ant.scm
index cb48c4226c..08a4c996f9 100644
--- a/guix/build-system/ant.scm
+++ b/guix/build-system/ant.scm
@@ -110,8 +110,7 @@
                     (test-exclude (list "**/Abstract*.java"))
                     (source-dir "src")
                     (test-dir "src/test")
-                    (phases '(@ (guix build ant-build-system)
-                                %standard-phases))
+                    (phases '%standard-phases)
                     (outputs '("out"))
                     (search-paths '())
                     (system (%current-system))
@@ -124,7 +123,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (ant-build #:name #$name
                      #:source #+source
                      #:make-flags #$make-flags
@@ -141,8 +140,9 @@
                      #:test-dir #$test-dir
                      #:phases #$phases
                      #:outputs #$(outputs->gexp outputs)
-                     #:search-paths '#$(map search-path-specification->sexp
-                                            search-paths)
+                     #:search-paths '#$(sexp->gexp
+                                        (map search-path-specification->sexp
+                                             search-paths))
                      #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad  ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/asdf.scm b/guix/build-system/asdf.scm
index 5f01d7ccce..7bf2f97992 100644
--- a/guix/build-system/asdf.scm
+++ b/guix/build-system/asdf.scm
@@ -96,8 +96,7 @@
 
 (define* (asdf-build/source name inputs
                             #:key source outputs
-                            (phases '(@ (guix build asdf-build-system)
-                                        %standard-phases/source))
+                            (phases '%standard-phases/source)
                             (search-paths '())
                             (system (%current-system))
                             (guile #f)
@@ -106,14 +105,15 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (asdf-build/source #:name #$name
                              #:source #+source
                              #:system #$system
                              #:phases #$phases
                              #:outputs #$(outputs->gexp outputs)
-                             #:search-paths '#$(map search-path-specification->sexp
-                                                    search-paths)
+                             #:search-paths '#$(sexp->gexp
+                                                (map search-path-specification->sexp
+                                                     search-paths))
                              #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
@@ -272,8 +272,7 @@ set up using CL source package conventions."
                  (asd-files ''())
                  (asd-systems ''())
                  (test-asd-file #f)
-                 (phases '(@ (guix build asdf-build-system)
-                             %standard-phases))
+                 (phases '%standard-phases)
                  (search-paths '())
                  (system (%current-system))
                  (guile #f)
@@ -295,7 +294,7 @@ set up using CL source package conventions."
     (define builder
       (with-imported-modules imported-modules
         #~(begin
-            (use-modules #$@modules)
+            (use-modules #$@(sexp->gexp modules))
             (parameterize ((%lisp (string-append
                                    (assoc-ref %build-inputs #$lisp-type)
                                    "/bin/" #$lisp-type))
@@ -309,8 +308,9 @@ set up using CL source package conventions."
                           #:tests? #$tests?
                           #:phases #$phases
                           #:outputs #$(outputs->gexp outputs)
-                          #:search-paths '#$(map search-path-specification->sexp
-                                                 search-paths)
+                          #:search-paths '#$(sexp->gexp
+                                             (map search-path-specification->sexp
+                                                  search-paths))
                           #:inputs #$(input-tuples->gexp inputs))))))
 
     (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/cargo.scm b/guix/build-system/cargo.scm
index d29265de7d..0af0ce0233 100644
--- a/guix/build-system/cargo.scm
+++ b/guix/build-system/cargo.scm
@@ -84,8 +84,7 @@ to NAME and VERSION."
                       (features ''())
                       (skip-build? #f)
                       (install-source? #t)
-                      (phases '(@ (guix build cargo-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (outputs '("out"))
                       (search-paths '())
                       (system (%current-system))
@@ -98,21 +97,23 @@ to NAME and VERSION."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (cargo-build #:name #$name
                        #:source #+source
                        #:system #$system
                        #:test-target #$test-target
                        #:vendor-dir #$vendor-dir
-                       #:cargo-build-flags #$cargo-build-flags
-                       #:cargo-test-flags #$cargo-test-flags
-                       #:cargo-package-flags #$cargo-package-flags
-                       #:features #$features
+                       #:cargo-build-flags #$(sexp->gexp cargo-build-flags)
+                       #:cargo-test-flags #$(sexp->gexp cargo-test-flags)
+                       #:cargo-package-flags #$(sexp->gexp cargo-package-flags)
+                       #:features #$(sexp->gexp features)
                        #:skip-build? #$skip-build?
                        #:install-source? #$install-source?
                        #:tests? #$(and tests? (not skip-build?))
-                       #:phases #$phases
+                       #:phases #$(if (pair? phases)
+                                      (sexp->gexp phases)
+                                      phases)
                        #:outputs (list #$@(map (lambda (name)
                                                  #~(cons #$name
                                                          (ungexp output name)))
@@ -120,8 +121,9 @@ to NAME and VERSION."
                        #:inputs (map (lambda (tuple)
                                        (apply cons tuple))
                                      '#$inputs)
-                       #:search-paths '#$(map search-path-specification->sexp
-                                             search-paths)))))
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))))))
 
   (gexp->derivation name builder
                     #:system system
diff --git a/guix/build-system/chicken.scm b/guix/build-system/chicken.scm
index 0989e7a79f..c6978266fc 100644
--- a/guix/build-system/chicken.scm
+++ b/guix/build-system/chicken.scm
@@ -75,8 +75,7 @@
 (define* (chicken-build name inputs
                         #:key
                         source
-                        (phases '(@ (guix build chicken-build-system)
-                                    %standard-phases))
+                        (phases '%standard-phases)
                         (outputs '("out"))
                         (search-paths '())
                         (egg-name "")
@@ -92,14 +91,15 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (chicken-build #:name #$name
                          #:source #+source
                          #:system #$system
                          #:phases #$phases
                          #:outputs #$(outputs->gexp outputs)
-                         #:search-paths '#$(map search-path-specification->sexp
-                                                search-paths)
+                         #:search-paths '#$(sexp->gexp
+                                            (map search-path-specification->sexp
+                                                 search-paths))
                          #:egg-name #$egg-name
                          #:unpack-path #$unpack-path
                          #:build-flags #$build-flags
diff --git a/guix/build-system/clojure.scm b/guix/build-system/clojure.scm
index e2ad67e3b6..39b7f44e89 100644
--- a/guix/build-system/clojure.scm
+++ b/guix/build-system/clojure.scm
@@ -137,7 +137,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (clojure-build #:name #$name
                          #:source #+source
@@ -162,8 +162,9 @@
 
                          #:phases #$phases
                          #:outputs #$(outputs->gexp outputs)
-                         #:search-paths '#$(map search-path-spec->sexp
-                                                search-paths)
+                         #:search-paths '#$(sexp->gexp
+                                            (map search-path-spec->sexp
+                                                 search-paths))
                          #:system #$system
                          #:inputs #$(input-tuples->gexp inputs)))))
 
diff --git a/guix/build-system/cmake.scm b/guix/build-system/cmake.scm
index f9ac2befc9..80059217c2 100644
--- a/guix/build-system/cmake.scm
+++ b/guix/build-system/cmake.scm
@@ -113,8 +113,7 @@
                       (strip-flags ''("--strip-debug"))
                       (strip-directories ''("lib" "lib64" "libexec"
                                             "bin" "sbin"))
-                      (phases '(@ (guix build cmake-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (system (%current-system))
                       (substitutable? #t)
                       (imported-modules %cmake-build-system-modules)
@@ -125,17 +124,22 @@ provides a 'CMakeLists.txt' file as its build system."
   (define build
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           #$(with-build-variables inputs outputs
               #~(cmake-build #:source #+source
                              #:system #$system
                              #:outputs %outputs
                              #:inputs %build-inputs
-                             #:search-paths '#$(map search-path-specification->sexp
-                                                    search-paths)
-                             #:phases #$phases
-                             #:configure-flags #$configure-flags
+                             #:search-paths '#$(sexp->gexp
+                                                (map search-path-specification->sexp
+                                                     search-paths))
+                             #:phases #$(if (pair? phases)
+                                            (sexp->gexp phases)
+                                            phases)
+                             #:configure-flags #$(if (pair? configure-flags)
+                                                     (sexp->gexp configure-flags)
+                                                     configure-flags)
                              #:make-flags #$make-flags
                              #:out-of-source? #$out-of-source?
                              #:build-type #$build-type
@@ -146,8 +150,8 @@ provides a 'CMakeLists.txt' file as its build system."
                              #:validate-runpath? #$validate-runpath?
                              #:patch-shebangs? #$patch-shebangs?
                              #:strip-binaries? #$strip-binaries?
-                             #:strip-flags #$strip-flags
-                             #:strip-directories #$strip-directories)))))
+                             #:strip-flags #$(sexp->gexp strip-flags)
+                             #:strip-directories #$(sexp->gexp strip-directories))))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
                                                   system #:graft? #f)))
@@ -184,8 +188,7 @@ provides a 'CMakeLists.txt' file as its build system."
                                             "--enable-deterministic-archives"))
                             (strip-directories ''("lib" "lib64" "libexec"
                                                   "bin" "sbin"))
-                            (phases '(@ (guix build cmake-build-system)
-                                        %standard-phases))
+                            (phases '%standard-phases)
                             (substitutable? #t)
                             (system (%current-system))
                             (build (nix-system->gnu-triplet system))
diff --git a/guix/build-system/copy.scm b/guix/build-system/copy.scm
index 8dea0b4c6b..4894ba46fb 100644
--- a/guix/build-system/copy.scm
+++ b/guix/build-system/copy.scm
@@ -108,16 +108,21 @@
                             #:system #$system
                             #:outputs %outputs
                             #:inputs %build-inputs
-                            #:install-plan #$install-plan
-                            #:search-paths '#$(map search-path-specification->sexp
-                                                   search-paths)
-                            #:phases #$phases
+                            #:install-plan #$(if (pair? install-plan)
+                                                 (sexp->gexp install-plan)
+                                                 install-plan)
+                            #:search-paths '#$(sexp->gexp
+                                               (map search-path-specification->sexp
+                                                    search-paths))
+                            #:phases #$(if (pair? phases)
+                                           (sexp->gexp phases)
+                                           phases)
                             #:out-of-source? #$out-of-source?
                             #:validate-runpath? #$validate-runpath?
                             #:patch-shebangs? #$patch-shebangs?
                             #:strip-binaries? #$strip-binaries?
-                            #:strip-flags #$strip-flags
-                            #:strip-directories #$strip-directories)))))
+                            #:strip-flags #$(sexp->gexp strip-flags)
+                            #:strip-directories #$(sexp->gexp strip-directories))))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
                                                   system #:graft? #f)))
diff --git a/guix/build-system/dub.scm b/guix/build-system/dub.scm
index 58a72fe828..55ad7decb8 100644
--- a/guix/build-system/dub.scm
+++ b/guix/build-system/dub.scm
@@ -63,8 +63,7 @@
                     (tests? #t)
                     (test-target #f)
                     (dub-build-flags ''())
-                    (phases '(@ (guix build dub-build-system)
-                                %standard-phases))
+                    (phases '%standard-phases)
                     (outputs '("out"))
                     (search-paths '())
                     (system (%current-system))
@@ -76,7 +75,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (dub-build #:name #$name
                      #:source #+source
                      #:system #$system
@@ -85,8 +84,9 @@
                      #:tests? #$tests?
                      #:phases #$phases
                      #:outputs #$(outputs->gexp outputs)
-                     #:search-paths '#$(map search-path-specification->sexp
-                                            search-paths)
+                     #:search-paths '#$(sexp->gexp
+                                        (map search-path-specification->sexp
+                                             search-paths))
                      #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/emacs.scm b/guix/build-system/emacs.scm
index 0a8f828b3d..3df68789ff 100644
--- a/guix/build-system/emacs.scm
+++ b/guix/build-system/emacs.scm
@@ -87,8 +87,7 @@
                       (tests? #f)
                       (parallel-tests? #t)
                       (test-command ''("make" "check"))
-                      (phases '(@ (guix build emacs-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (outputs '("out"))
                       (include (quote %default-include))
                       (exclude (quote %default-exclude))
@@ -103,7 +102,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (emacs-build #:name #$name
                        #:source #+source
                        #:system #$system
@@ -114,8 +113,9 @@
                        #:outputs #$(outputs->gexp outputs)
                        #:include #$include
                        #:exclude #$exclude
-                       #:search-paths '#$(map search-path-specification->sexp
-                                              search-paths)
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))
                        #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/font.scm b/guix/build-system/font.scm
index e7160ff426..74dc80b5db 100644
--- a/guix/build-system/font.scm
+++ b/guix/build-system/font.scm
@@ -77,8 +77,7 @@
                      (tests? #t)
                      (test-target "test")
                      (configure-flags ''())
-                     (phases '(@ (guix build font-build-system)
-                                 %standard-phases))
+                     (phases '%standard-phases)
                      (outputs '("out"))
                      (search-paths '())
                      (system (%current-system))
@@ -99,10 +98,13 @@
                             #:system #$system
                             #:test-target #$test-target
                             #:tests? #$tests?
-                            #:phases #$phases
+                            #:phases #$(if (pair? phases)
+                                           (sexp->gexp phases)
+                                           phases)
                             #:outputs %outputs
-                            #:search-paths '#$(map search-path-specification->sexp
-                                                   search-paths)
+                            #:search-paths '#$(sexp->gexp
+                                               (map search-path-specification->sexp
+                                                    search-paths))
                             #:inputs %build-inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/glib-or-gtk.scm b/guix/build-system/glib-or-gtk.scm
index 6c09b5a3b7..2df49a2495 100644
--- a/guix/build-system/glib-or-gtk.scm
+++ b/guix/build-system/glib-or-gtk.scm
@@ -137,16 +137,19 @@
   (define build
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           #$(with-build-variables inputs outputs
               #~(glib-or-gtk-build #:source #+source
                                    #:system #$system
                                    #:outputs %outputs
                                    #:inputs %build-inputs
-                                   #:search-paths '#$(map search-path-specification->sexp
-                                                          search-paths)
-                                   #:phases #$phases
+                                   #:search-paths '#$(sexp->gexp
+                                                      (map search-path-specification->sexp
+                                                           search-paths))
+                                   #:phases #$(if (pair? phases)
+                                                  (sexp->gexp phases)
+                                                  phases)
                                    #:glib-or-gtk-wrap-excluded-outputs
                                    #$glib-or-gtk-wrap-excluded-outputs
                                    #:configure-flags #$configure-flags
@@ -159,8 +162,9 @@
                                    #:validate-runpath? #$validate-runpath?
                                    #:patch-shebangs? #$patch-shebangs?
                                    #:strip-binaries? #$strip-binaries?
-                                   #:strip-flags #$strip-flags
-                                   #:strip-directories #$strip-directories)))))
+                                   #:strip-flags #$(sexp->gexp strip-flags)
+                                   #:strip-directories
+                                   #$(sexp->gexp strip-directories))))))
 
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/gnu.scm b/guix/build-system/gnu.scm
index 613deb7bb0..3fb1a241dd 100644
--- a/guix/build-system/gnu.scm
+++ b/guix/build-system/gnu.scm
@@ -330,6 +330,12 @@ standard packages used as implicit inputs of the GNU build system."
   ;; Typical names of Autotools "bootstrap" scripts.
   '("bootstrap" "bootstrap.sh" "autogen.sh"))
 
+(define %strip-flags
+  #~'("--strip-unneeded" "--enable-deterministic-archives"))
+
+(define %strip-directories
+  #~'("lib" "lib64" "libexec" "bin" "sbin"))
+
 (define* (gnu-build name inputs
                     #:key
                     guile source
@@ -345,10 +351,8 @@ standard packages used as implicit inputs of the GNU build system."
                     (parallel-tests? #t)
                     (patch-shebangs? #t)
                     (strip-binaries? #t)
-                    (strip-flags ''("--strip-unneeded"
-                                    "--enable-deterministic-archives"))
-                    (strip-directories ''("lib" "lib64" "libexec"
-                                          "bin" "sbin"))
+                    (strip-flags %strip-flags)
+                    (strip-directories %strip-directories)
                     (validate-runpath? #t)
                     (make-dynamic-linker-cache? #t)
                     (license-file-regexp %license-file-regexp)
@@ -381,7 +385,7 @@ are allowed to refer to."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           #$(with-build-variables inputs outputs
               #~(gnu-build #:source #+source
@@ -389,13 +393,20 @@ are allowed to refer to."
                            #:build #$build
                            #:outputs %outputs
                            #:inputs %build-inputs
-                           #:search-paths '#$(map search-path-specification->sexp
-                                                  search-paths)
-                           #:phases #$phases
+                           #:search-paths '#$(sexp->gexp
+                                              (map search-path-specification->sexp
+                                                   search-paths))
+                           #:phases #$(if (pair? phases)
+                                          (sexp->gexp phases)
+                                          phases)
                            #:locale #$locale
-                           #:bootstrap-scripts #$bootstrap-scripts
-                           #:configure-flags #$configure-flags
-                           #:make-flags #$make-flags
+                           #:bootstrap-scripts #$(sexp->gexp bootstrap-scripts)
+                           #:configure-flags #$(if (pair? configure-flags)
+                                                   (sexp->gexp configure-flags)
+                                                   configure-flags)
+                           #:make-flags #$(if (pair? make-flags)
+                                              (sexp->gexp make-flags)
+                                              make-flags)
                            #:out-of-source? #$out-of-source?
                            #:tests? #$tests?
                            #:test-target #$test-target
@@ -472,10 +483,8 @@ is one of `host' or `target'."
                           (parallel-build? #t) (parallel-tests? #t)
                           (patch-shebangs? #t)
                           (strip-binaries? #t)
-                          (strip-flags ''("--strip-unneeded"
-                                          "--enable-deterministic-archives"))
-                          (strip-directories ''("lib" "lib64" "libexec"
-                                                "bin" "sbin"))
+                          (strip-flags %strip-flags)
+                          (strip-directories %strip-directories)
                           (validate-runpath? #t)
 
                           ;; We run 'ldconfig' to generate ld.so.cache and it
@@ -498,7 +507,7 @@ cross-built inputs, and NATIVE-INPUTS are inputs that run on the build
 platform."
   (define builder
     #~(begin
-        (use-modules #$@modules)
+        (use-modules #$@(sexp->gexp modules))
 
         (define %build-host-inputs
           (map (lambda (tuple)
@@ -523,11 +532,13 @@ platform."
                    #:outputs %outputs
                    #:inputs %build-target-inputs
                    #:native-inputs %build-host-inputs
-                   #:search-paths '#$(map search-path-specification->sexp
-                                          search-paths)
-                   #:native-search-paths '#$(map
-                                             search-path-specification->sexp
-                                             native-search-paths)
+                   #:search-paths '#$(sexp->gexp
+                                      (map search-path-specification->sexp
+                                           search-paths))
+                   #:native-search-paths '#$(sexp->gexp
+                                             (map
+                                              search-path-specification->sexp
+                                              native-search-paths))
                    #:phases #$phases
                    #:locale #$locale
                    #:bootstrap-scripts #$bootstrap-scripts
diff --git a/guix/build-system/go.scm b/guix/build-system/go.scm
index 4c8156e73c..392f2d9b7b 100644
--- a/guix/build-system/go.scm
+++ b/guix/build-system/go.scm
@@ -113,8 +113,7 @@ it, defaulting to full VERSION if a pseudo-version pattern is not recognized."
 (define* (go-build name inputs
                    #:key
                    source
-                   (phases '(@ (guix build go-build-system)
-                               %standard-phases))
+                   (phases '%standard-phases)
                    (outputs '("out"))
                    (search-paths '())
                    (install-source? #t)
@@ -138,8 +137,9 @@ it, defaulting to full VERSION if a pseudo-version pattern is not recognized."
                     #:system #$system
                     #:phases #$phases
                     #:outputs #$(outputs->gexp outputs)
-                    #:search-paths '#$(map search-path-specification->sexp
-                                           search-paths)
+                    #:search-paths '#$(sexp->gexp
+                                       (map search-path-specification->sexp
+                                            search-paths))
                     #:install-source? #$install-source?
                     #:import-path #$import-path
                     #:unpack-path #$unpack-path
diff --git a/guix/build-system/haskell.scm b/guix/build-system/haskell.scm
index b7ee72557c..67c8593cf6 100644
--- a/guix/build-system/haskell.scm
+++ b/guix/build-system/haskell.scm
@@ -129,8 +129,7 @@ version REVISION."
                         (parallel-build? #f)
                         (configure-flags ''())
                         (extra-directories ''())
-                        (phases '(@ (guix build haskell-build-system)
-                                    %standard-phases))
+                        (phases '%standard-phases)
                         (outputs '("out" "static"))
                         (search-paths '())
                         (system (%current-system))
@@ -143,7 +142,7 @@ provides a 'Setup.hs' file as its build system."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (haskell-build #:name #$name
                          #:source #+source
@@ -159,8 +158,9 @@ provides a 'Setup.hs' file as its build system."
                          #:haddock? #$haddock?
                          #:phases #$phases
                          #:outputs #$(outputs->gexp outputs)
-                         #:search-paths '#$(map search-path-specification->sexp
-                                                search-paths)
+                         #:search-paths '#$(sexp->gexp
+                                            (map search-path-specification->sexp
+                                                 search-paths))
                          #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/julia.scm b/guix/build-system/julia.scm
index 6e006af527..5b824d7f0a 100644
--- a/guix/build-system/julia.scm
+++ b/guix/build-system/julia.scm
@@ -78,8 +78,7 @@
 (define* (julia-build name inputs
                       #:key source
                       (tests? #t)
-                      (phases '(@ (guix build julia-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (outputs '("out"))
                       (search-paths '())
                       (system (%current-system))
@@ -92,15 +91,16 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (julia-build #:name #$name
                        #:source #+source
                        #:system #$system
                        #:tests? #$tests?
                        #:phases #$phases
                        #:outputs #$(outputs->gexp outputs)
-                       #:search-paths '#$(map search-path-specification->sexp
-                                              search-paths)
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))
                        #:inputs #$(input-tuples->gexp inputs)
                        #:julia-package-name #$julia-package-name))))
 
diff --git a/guix/build-system/linux-module.scm b/guix/build-system/linux-module.scm
index 3a29a93bd7..84570b923a 100644
--- a/guix/build-system/linux-module.scm
+++ b/guix/build-system/linux-module.scm
@@ -155,8 +155,7 @@
                              source target
                              (search-paths '())
                              (tests? #t)
-                             (phases '(@ (guix build linux-module-build-system)
-                                         %standard-phases))
+                             (phases '%standard-phases)
                              (outputs '("out"))
                              (make-flags ''())
                              (system (%current-system))
@@ -170,11 +169,12 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (linux-module-build #:name #$name
                               #:source #+source
-                              #:search-paths '#$(map search-path-specification->sexp
-                                                     search-paths)
+                              #:search-paths '#$(sexp->gexp
+                                                 (map search-path-specification->sexp
+                                                      search-paths))
                               #:phases #$phases
                               #:system #$system
                               #:target #$target
@@ -202,8 +202,7 @@
           (search-paths '())
           (native-search-paths '())
           (tests? #f)
-          (phases '(@ (guix build linux-module-build-system)
-                      %standard-phases))
+          (phases '%standard-phases)
           (system (%current-system))
           (substitutable? #t)
           (imported-modules
@@ -213,7 +212,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (define %build-host-inputs
             '#+(input-tuples->gexp build-inputs))
@@ -232,8 +231,9 @@
                               #:inputs %build-target-inputs
                               #:native-inputs %build-host-inputs
                               #:search-paths
-                              '#$(map search-path-specification->sexp
-                                      search-paths)
+                              '#$(sexp->gexp
+                                  (map search-path-specification->sexp
+                                       search-paths))
                               #:native-search-paths
                               '#$(map
                                   search-path-specification->sexp
diff --git a/guix/build-system/maven.scm b/guix/build-system/maven.scm
index 04358e6240..0af5922692 100644
--- a/guix/build-system/maven.scm
+++ b/guix/build-system/maven.scm
@@ -157,8 +157,7 @@
                       (strip-flags ''("--strip-debug"))
                       (strip-directories ''("lib" "lib64" "libexec"
                                             "bin" "sbin"))
-                      (phases '(@ (guix build maven-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (system (%current-system))
                       (imported-modules %maven-build-system-modules)
                       (modules '((guix build maven-build-system)
@@ -169,13 +168,14 @@ provides its own binaries."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (maven-build #:source #+source
                        #:system #$system
                        #:outputs #$(outputs->gexp outputs)
                        #:inputs #$(input-tuples->gexp inputs)
-                       #:search-paths '#$(map search-path-specification->sexp
-                                              search-paths)
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))
                        #:phases #$phases
                        #:exclude '#$exclude
                        #:local-packages '#$local-packages
@@ -184,8 +184,8 @@ provides its own binaries."
                        #:validate-runpath? #$validate-runpath?
                        #:patch-shebangs? #$patch-shebangs?
                        #:strip-binaries? #$strip-binaries?
-                       #:strip-flags #$strip-flags
-                       #:strip-directories #$strip-directories))))
+                       #:strip-flags #$(sexp->gexp strip-flags)
+                       #:strip-directories #$(sexp->gexp strip-directories)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
                                                   system #:graft? #f)))
diff --git a/guix/build-system/meson.scm b/guix/build-system/meson.scm
index 19fbe54758..5adc0f92c8 100644
--- a/guix/build-system/meson.scm
+++ b/guix/build-system/meson.scm
@@ -107,8 +107,7 @@
                                             "bin" "sbin"))
                       (elf-directories ''("lib" "lib64" "libexec"
                                           "bin" "sbin"))
-                      (phases '(@ (guix build meson-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (system (%current-system))
                       (imported-modules %meson-build-system-modules)
                       (modules '((guix build meson-build-system)
@@ -120,24 +119,26 @@ has a 'meson.build' file."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (define build-phases
-            #$(if glib-or-gtk?
-                  phases
-                  #~(modify-phases #$phases
-                      (delete 'glib-or-gtk-compile-schemas)
-                      (delete 'glib-or-gtk-wrap))))
+            #$(let ((phases (if (pair? phases) (sexp->gexp phases) phases)))
+                (if glib-or-gtk?
+                    phases
+                    #~(modify-phases #$phases
+                        (delete 'glib-or-gtk-compile-schemas)
+                        (delete 'glib-or-gtk-wrap)))))
 
           #$(with-build-variables inputs outputs
               #~(meson-build #:source #+source
                              #:system #$system
                              #:outputs %outputs
                              #:inputs %build-inputs
-                             #:search-paths '#$(map search-path-specification->sexp
-                                                    search-paths)
+                             #:search-paths '#$(sexp->gexp
+                                                (map search-path-specification->sexp
+                                                     search-paths))
                              #:phases build-phases
-                             #:configure-flags #$configure-flags
+                             #:configure-flags #$(sexp->gexp configure-flags)
                              #:build-type #$build-type
                              #:tests? #$tests?
                              #:test-target #$test-target
@@ -146,9 +147,9 @@ has a 'meson.build' file."
                              #:validate-runpath? #$validate-runpath?
                              #:patch-shebangs? #$patch-shebangs?
                              #:strip-binaries? #$strip-binaries?
-                             #:strip-flags #$strip-flags
-                             #:strip-directories #$strip-directories
-                             #:elf-directories #$elf-directories)))))
+                             #:strip-flags #$(sexp->gexp strip-flags)
+                             #:strip-directories #$(sexp->gexp strip-directories)
+                             #:elf-directories #$(sexp->gexp elf-directories))))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
                                                   system #:graft? #f)))
diff --git a/guix/build-system/minify.scm b/guix/build-system/minify.scm
index 751312a523..3256b5d30b 100644
--- a/guix/build-system/minify.scm
+++ b/guix/build-system/minify.scm
@@ -76,8 +76,7 @@
                        #:key
                        source
                        (javascript-files #f)
-                       (phases '(@ (guix build minify-build-system)
-                                   %standard-phases))
+                       (phases '%standard-phases)
                        (outputs '("out"))
                        (system (%current-system))
                        search-paths
@@ -89,14 +88,15 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (minify-build #:name #$name
                         #:source #+source
                         #:javascript-files #$javascript-files
                         #:phases #$phases
                         #:outputs #$(outputs->gexp outputs)
-                        #:search-paths '#$(map search-path-specification->sexp
-                                               search-paths)
+                        #:search-paths '#$(sexp->gexp
+                                           (map search-path-specification->sexp
+                                                search-paths))
                         #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/node.scm b/guix/build-system/node.scm
index c174da98aa..73a6f152dd 100644
--- a/guix/build-system/node.scm
+++ b/guix/build-system/node.scm
@@ -81,8 +81,7 @@ registry."
                      source
                      (npm-flags ''())
                      (tests? #t)
-                     (phases '(@ (guix build node-build-system)
-                                 %standard-phases))
+                     (phases '%standard-phases)
                      (outputs '("out"))
                      (search-paths '())
                      (system (%current-system))
@@ -96,7 +95,7 @@ registry."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (node-build #:name #$name
                       #:source #+source
                       #:system #$system
@@ -104,8 +103,9 @@ registry."
                       #:tests? #$tests?
                       #:phases #$phases
                       #:outputs #$(outputs->gexp outputs)
-                      #:search-paths '#$(map search-path-specification->sexp
-                                             search-paths)
+                      #:search-paths '#$(sexp->gexp
+                                         (map search-path-specification->sexp
+                                              search-paths))
                       #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/perl.scm b/guix/build-system/perl.scm
index 32045ef6de..db0a916fb2 100644
--- a/guix/build-system/perl.scm
+++ b/guix/build-system/perl.scm
@@ -100,17 +100,20 @@ provides a `Makefile.PL' file as its build system."
   (define build
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           #$(with-build-variables inputs outputs
               #~(perl-build #:name #$name
                             #:source #+source
-                            #:search-paths '#$(map search-path-specification->sexp
-                                                   search-paths)
+                            #:search-paths '#$(sexp->gexp
+                                               (map search-path-specification->sexp
+                                                    search-paths))
                             #:make-maker? #$make-maker?
                             #:make-maker-flags #$make-maker-flags
-                            #:module-build-flags #$module-build-flags
-                            #:phases #$phases
+                            #:module-build-flags #$(sexp->gexp module-build-flags)
+                            #:phases #$(if (pair? phases)
+                                           (sexp->gexp phases)
+                                           phases)
                             #:system #$system
                             #:test-target "test"
                             #:tests? #$tests?
diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index 018fda9b20..efade6f74b 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -175,8 +175,7 @@ pre-defined variants."
                        (test-target "test")
                        (use-setuptools? #t)
                        (configure-flags ''())
-                       (phases '(@ (guix build python-build-system)
-                                   %standard-phases))
+                       (phases '%standard-phases)
                        (outputs '("out"))
                        (search-paths '())
                        (system (%current-system))
@@ -189,7 +188,7 @@ provides a 'setup.py' file as its build system."
   (define build
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           #$(with-build-variables inputs outputs
               #~(python-build #:name #$name
@@ -199,10 +198,13 @@ provides a 'setup.py' file as its build system."
                               #:system #$system
                               #:test-target #$test-target
                               #:tests? #$tests?
-                              #:phases #$phases
+                              #:phases #$(if (pair? phases)
+                                             (sexp->gexp phases)
+                                             phases)
                               #:outputs %outputs
-                              #:search-paths '#$(map search-path-specification->sexp
-                                                     search-paths)
+                              #:search-paths '#$(sexp->gexp
+                                                 (map search-path-specification->sexp
+                                                      search-paths))
                               #:inputs %build-inputs)))))
 
 
diff --git a/guix/build-system/qt.scm b/guix/build-system/qt.scm
index 7df431a68d..063fa7bedc 100644
--- a/guix/build-system/qt.scm
+++ b/guix/build-system/qt.scm
@@ -123,8 +123,7 @@
                    (strip-flags ''("--strip-debug"))
                    (strip-directories ''("lib" "lib64" "libexec"
                                          "bin" "sbin"))
-                   (phases '(@ (guix build qt-build-system)
-                               %standard-phases))
+                   (phases '%standard-phases)
                    (qt-wrap-excluded-outputs ''())
                    (system (%current-system))
                    (imported-modules %qt-build-system-modules)
@@ -135,13 +134,14 @@ provides a 'CMakeLists.txt' file as its build system."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (qt-build #:source #+source
                     #:system #$system
                     #:outputs #$(outputs->gexp outputs)
                     #:inputs #$(input-tuples->gexp inputs)
-                    #:search-paths '#$(map search-path-specification->sexp
-                                           search-paths)
+                    #:search-paths '#$(sexp->gexp
+                                       (map search-path-specification->sexp
+                                            search-paths))
                     #:phases #$phases
                     #:qt-wrap-excluded-outputs #$qt-wrap-excluded-outputs
                     #:configure-flags #$configure-flags
@@ -191,8 +191,7 @@ provides a 'CMakeLists.txt' file as its build system."
                                          "--enable-deterministic-archives"))
                          (strip-directories ''("lib" "lib64" "libexec"
                                                "bin" "sbin"))
-                         (phases '(@ (guix build qt-build-system)
-                                     %standard-phases))
+                         (phases '%standard-phases)
                          (system (%current-system))
                          (build (nix-system->gnu-triplet system))
                          (imported-modules %qt-build-system-modules)
@@ -204,7 +203,7 @@ build system."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (define %build-host-inputs
             #+(input-tuples->gexp build-inputs))
@@ -223,8 +222,9 @@ build system."
                     #:outputs %outputs
                     #:inputs %build-target-inputs
                     #:native-inputs %build-host-inputs
-                    #:search-paths '#$(map search-path-specification->sexp
-                                           search-paths)
+                    #:search-paths '#$(sexp->gexp
+                                       (map search-path-specification->sexp
+                                            search-paths))
                     #:native-search-paths '#$(map
                                               search-path-specification->sexp
                                               native-search-paths)
diff --git a/guix/build-system/r.scm b/guix/build-system/r.scm
index 12b7df66a6..c4425e0a12 100644
--- a/guix/build-system/r.scm
+++ b/guix/build-system/r.scm
@@ -109,8 +109,7 @@ release corresponding to NAME and VERSION."
                   (tests? #t)
                   (test-target "tests")
                   (configure-flags ''())
-                  (phases '(@ (guix build r-build-system)
-                              %standard-phases))
+                  (phases '%standard-phases)
                   (outputs '("out"))
                   (search-paths '())
                   (system (%current-system))
@@ -123,7 +122,7 @@ release corresponding to NAME and VERSION."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (r-build #:name #$name
                    #:source #+source
                    #:configure-flags #$configure-flags
@@ -132,8 +131,9 @@ release corresponding to NAME and VERSION."
                    #:test-target #$test-target
                    #:phases #$phases
                    #:outputs #$(outputs->gexp outputs)
-                   #:search-paths '#$(map search-path-specification->sexp
-                                          search-paths)
+                   #:search-paths '#$(sexp->gexp
+                                      (map search-path-specification->sexp
+                                           search-paths))
                    #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/rakudo.scm b/guix/build-system/rakudo.scm
index eab41e2cb9..05a4d9c2ad 100644
--- a/guix/build-system/rakudo.scm
+++ b/guix/build-system/rakudo.scm
@@ -103,8 +103,7 @@
                        source
                        (search-paths '())
                        (tests? #t)
-                       (phases '(@ (guix build rakudo-build-system)
-                                   %standard-phases))
+                       (phases '%standard-phases)
                        (outputs '("out"))
                        (system (%current-system))
                        (guile #f)
@@ -117,11 +116,12 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (rakudo-build #:name #$name
                         #:source #+source
-                        #:search-paths '#$(map search-path-specification->sexp
-                                               search-paths)
+                        #:search-paths '#$(sexp->gexp
+                                           (map search-path-specification->sexp
+                                                search-paths))
                         #:phases #$phases
                         #:system #$system
                         #:tests? #$tests?
diff --git a/guix/build-system/renpy.scm b/guix/build-system/renpy.scm
index 5c65f55455..0ee73ec969 100644
--- a/guix/build-system/renpy.scm
+++ b/guix/build-system/renpy.scm
@@ -77,8 +77,7 @@
 (define* (renpy-build name inputs
                       #:key
                       source
-                      (phases '(@ (guix build renpy-build-system)
-                                  %standard-phases))
+                      (phases '%standard-phases)
                       (configure-flags ''())
                       (outputs '("out"))
                       (output "out")
@@ -93,7 +92,7 @@
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
           (renpy-build #:name #$name
                        #:source #+source
                        #:configure-flags #$configure-flags
@@ -102,8 +101,9 @@
                        #:outputs #$(outputs->gexp outputs)
                        #:output #$output
                        #:game #$game
-                       #:search-paths '#$(map search-path-specification->sexp
-                                              search-paths)
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))
                        #:inputs #$(input-tuples->gexp inputs)))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/ruby.scm b/guix/build-system/ruby.scm
index 8b02e0ff52..342daf7978 100644
--- a/guix/build-system/ruby.scm
+++ b/guix/build-system/ruby.scm
@@ -80,8 +80,7 @@ NAME and VERSION."
                      (gem-flags ''())
                      (test-target "test")
                      (tests? #t)
-                     (phases '(@ (guix build ruby-build-system)
-                                 %standard-phases))
+                     (phases '%standard-phases)
                      (outputs '("out"))
                      (search-paths '())
                      (system (%current-system))
@@ -92,7 +91,7 @@ NAME and VERSION."
   "Build SOURCE using RUBY and INPUTS."
   (define build
     #~(begin
-        (use-modules #$@modules)
+        (use-modules #$@(sexp->gexp modules))
 
         #$(with-build-variables inputs outputs
             #~(ruby-build #:name #$name
@@ -101,10 +100,13 @@ NAME and VERSION."
                           #:gem-flags #$gem-flags
                           #:test-target #$test-target
                           #:tests? #$tests?
-                          #:phases #$phases
+                          #:phases #$(if (pair? phases)
+                                         (sexp->gexp phases)
+                                         phases)
                           #:outputs %outputs
-                          #:search-paths '#$(map search-path-specification->sexp
-                                                 search-paths)
+                          #:search-paths '#$(sexp->gexp
+                                             (map search-path-specification->sexp
+                                                  search-paths))
                           #:inputs %build-inputs))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/build-system/scons.scm b/guix/build-system/scons.scm
index 6af6998d26..07fd008d0d 100644
--- a/guix/build-system/scons.scm
+++ b/guix/build-system/scons.scm
@@ -79,11 +79,10 @@
                       (source #f)
                       (tests? #t)
                       (scons-flags ''())
-                      (build-targets ''())
+                      (build-targets #~'())
                       (test-target "test")
-                      (install-targets ''("install"))
-                      (phases '(@ (guix build scons-build-system)
-                                  %standard-phases))
+                      (install-targets #~'("install"))
+                      (phases '%standard-phases)
                       (outputs '("out"))
                       (search-paths '())
                       (system (%current-system))
@@ -96,17 +95,19 @@ provides a 'SConstruct' file as its build system."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
+          (use-modules #$@(sexp->gexp modules))
 
           (scons-build #:name ,name
                        #:source #+source
-                       #:scons-flags #$scons-flags
+                       #:scons-flags #$(sexp->gexp scons-flags)
                        #:system #$system
                        #:build-targets #$build-targets
                        #:test-target #$test-target
                        #:tests? #$tests?
                        #:install-targets #$install-targets
-                       #:phases #$phases
+                       #:phases #$(if (pair? phases)
+                                      (sexp->gexp phases)
+                                      phases)
                        #:outputs (list #$@(map (lambda (name)
                                                  #~(cons #$name
                                                          (ungexp output name)))
@@ -114,8 +115,9 @@ provides a 'SConstruct' file as its build system."
                        #:inputs (map (lambda (tuple)
                                        (apply cons tuple))
                                      '#$inputs)
-                       #:search-paths '#$(map search-path-specification->sexp
-                                              search-paths)))))
+                       #:search-paths '#$(sexp->gexp
+                                          (map search-path-specification->sexp
+                                               search-paths))))))
 
   (gexp->derivation name builder
                     #:system system
diff --git a/guix/build-system/texlive.scm b/guix/build-system/texlive.scm
index 0a69d1f328..c7fa2e3add 100644
--- a/guix/build-system/texlive.scm
+++ b/guix/build-system/texlive.scm
@@ -144,24 +144,24 @@ level package ID."
   (define builder
     (with-imported-modules imported-modules
       #~(begin
-          (use-modules #$@modules)
-          (texlive-build #:name #$name
-                         #:source #+source
-                         #:tex-directory #$tex-directory
-                         #:build-targets #$build-targets
-                         #:tex-format #$tex-format
-                         #:system #$system
-                         #:tests? #$tests?
-                         #:phases #$phases
-                         #:outputs (list #$@(map (lambda (name)
-                                                   #~(cons #$name
-                                                           (ungexp output name)))
-                                                 outputs))
-                         #:inputs (map (lambda (tuple)
-                                         (apply cons tuple))
-                                       '#$inputs)
-                         #:search-paths '#$(map search-path-specification->sexp
-                                                search-paths)))))
+          (use-modules #$@(sexp->gexp modules))
+
+          #$(with-build-variables inputs outputs
+              #~(texlive-build #:name #$name
+                               #:source #+source
+                               #:tex-directory #$tex-directory
+                               #:build-targets #$build-targets
+                               #:tex-format #$tex-format
+                               #:system #$system
+                               #:tests? #$tests?
+                               #:phases #$(if (pair? phases)
+                                              (sexp->gexp phases)
+                                              phases)
+                               #:outputs %outputs
+                               #:inputs %build-inputs
+                               #:search-paths '#$(sexp->gexp
+                                                  (map search-path-specification->sexp
+                                                       search-paths)))))))
 
   (gexp->derivation name builder
                     #:system system
diff --git a/guix/build-system/trivial.scm b/guix/build-system/trivial.scm
index 0f89524231..73d452aea2 100644
--- a/guix/build-system/trivial.scm
+++ b/guix/build-system/trivial.scm
@@ -54,7 +54,10 @@
   "Run build expression BUILDER, an expression, for SYSTEM.  SOURCE is
 ignored."
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
-                                                  system #:graft? #f)))
+                                                  system #:graft? #f))
+                      (builder -> (if (pair? builder)
+                                      (sexp->gexp builder)
+                                      builder)))
     (gexp->derivation name (with-build-variables inputs outputs builder)
                       #:system system
                       #:target #f
@@ -72,7 +75,10 @@ ignored."
   "Run build expression BUILDER, an expression, for SYSTEM.  SOURCE is
 ignored."
   (mlet %store-monad  ((guile (package->derivation (or guile (default-guile))
-                                                   system #:graft? #f)))
+                                                   system #:graft? #f))
+                       (builder -> (if (pair? builder)
+                                       (sexp->gexp builder)
+                                       builder)))
     (gexp->derivation name (with-build-variables
                                (append build-inputs target-inputs)
                                outputs
diff --git a/guix/build-system/waf.scm b/guix/build-system/waf.scm
index db604e6ecf..e8cd5520b8 100644
--- a/guix/build-system/waf.scm
+++ b/guix/build-system/waf.scm
@@ -77,9 +77,8 @@
                     #:key source
                     (tests? #t)
                     (test-target "check")
-                    (configure-flags ''())
-                    (phases '(@ (guix build waf-build-system)
-                                %standard-phases))
+                    (configure-flags #~'())
+                    (phases '%standard-phases)
                     (outputs '("out"))
                     (search-paths '())
                     (system (%current-system))
@@ -91,7 +90,7 @@
 as its build system."
   (define build
     #~(begin
-        (use-modules #$@modules)
+        (use-modules #$@(sexp->gexp modules))
 
         #$(with-build-variables inputs outputs
             #~(waf-build #:name #$name
@@ -102,8 +101,9 @@ as its build system."
                          #:tests? #$tests?
                          #:phases #$phases
                          #:outputs %outputs
-                         #:search-paths '#$(map search-path-specification->sexp
-                                                search-paths)
+                         #:search-paths '#$(sexp->gexp
+                                            (map search-path-specification->sexp
+                                                 search-paths))
                          #:inputs %build-inputs))))
 
   (mlet %store-monad ((guile (package->derivation (or guile (default-guile))
diff --git a/guix/packages.scm b/guix/packages.scm
index cbe8004888..8b40c06000 100644
--- a/guix/packages.scm
+++ b/guix/packages.scm
@@ -769,7 +769,9 @@ specifies modules in scope when evaluating SNIPPET."
                            module
                            (map resolve-interface '#+modules))
                           ((@ (system base compile) compile)
-                           '#+snippet
+                           '#+(if (pair? snippet)
+                                  (sexp->gexp snippet)
+                                  snippet)
                            #:to 'value
                            #:opts %auto-compilation-options
                            #:env module))
diff --git a/guix/svn-download.scm b/guix/svn-download.scm
index b96151234c..28ad49977b 100644
--- a/guix/svn-download.scm
+++ b/guix/svn-download.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015, 2016, 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014, 2015, 2016, 2019, 2021 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Sree Harsha Totakura <sreeharsha@totakura.in>
 ;;; Copyright © 2017, 2019 Ricardo Wurmus <rekado@elephly.net>
 ;;;
@@ -134,7 +134,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
                               #$(svn-multi-reference-recursive? ref)
                               #:user-name #$(svn-multi-reference-user-name ref)
                               #:password #$(svn-multi-reference-password ref)))
-                 '#$(svn-multi-reference-locations ref)))))
+                 '#$(sexp->gexp (svn-multi-reference-locations ref))))))
 
   (mlet %store-monad ((guile (package->derivation guile system)))
     (gexp->derivation (or name "svn-checkout") build