build-system: Bags record their system and target.

* guix/build-system.scm (<bag>)[system, target]: New fields.
  (make-bag): Add #:system parameter and pass it to LOWER.
* gnu/packages/bootstrap.scm (make-raw-bag): Initialize 'system' field.
* guix/build-system/cmake.scm (lower): Likewise.
* guix/build-system/perl.scm (lower): Likewise.
* guix/build-system/python.scm (lower): Likewise.
* guix/build-system/ruby.scm (lower): Likewise.
* guix/build-system/trivial.scm (lower): Likewise.
* guix/build-system/gnu.scm (lower): Initialize 'system' and 'target'
  fields.
* guix/packages.scm (bag->derivation, bag->cross-derivation): New
  procedures.
  (package-derivation, package-cross-derivation): Use 'bag->derivation'.
* tests/packages.scm ("search paths"): Initialize 'system' and 'target'
  fields.
  ("package->bag", "package->bag, cross-compilation", "bag->derivation",
  "bag->derivation, cross-compilation"): New tests.

6 files changed, 13 insertions, 6 deletions

diff --git a/guix/build-system/cmake.scm b/guix/build-system/cmake.scm
index 0e750c0e11..85acc2d0b3 100644
--- a/guix/build-system/cmake.scm
+++ b/guix/build-system/cmake.scm
@@ -43,7 +43,7 @@
     (module-ref module 'cmake)))
 
 (define* (lower name
-                #:key source inputs native-inputs outputs target
+                #:key source inputs native-inputs outputs system target
                 (cmake (default-cmake))
                 #:allow-other-keys
                 #:rest arguments)
@@ -54,6 +54,7 @@
   (and (not target)                               ;XXX: no cross-compilation
        (bag
          (name name)
+         (system system)
          (host-inputs `(,@(if source
                               `(("source" ,source))
                               '())
diff --git a/guix/build-system/gnu.scm b/guix/build-system/gnu.scm
index c58dac10bb..d2c29d44b5 100644
--- a/guix/build-system/gnu.scm
+++ b/guix/build-system/gnu.scm
@@ -210,7 +210,7 @@ standard packages used as implicit inputs of the GNU build system."
 (define* (lower name
                 #:key source inputs native-inputs outputs target
                 (implicit-inputs? #t) (implicit-cross-inputs? #t)
-                (strip-binaries? #t)
+                (strip-binaries? #t) system
                 #:allow-other-keys
                 #:rest arguments)
   "Return a bag for NAME from the given arguments."
@@ -221,6 +221,7 @@ standard packages used as implicit inputs of the GNU build system."
 
   (bag
     (name name)
+    (system system) (target target)
     (build-inputs `(,@(if source
                           `(("source" ,source))
                           '())
diff --git a/guix/build-system/perl.scm b/guix/build-system/perl.scm
index 6cf8cbe13a..1a968f4150 100644
--- a/guix/build-system/perl.scm
+++ b/guix/build-system/perl.scm
@@ -43,7 +43,8 @@
     (module-ref module 'perl)))
 
 (define* (lower name
-                #:key source inputs native-inputs outputs target
+                #:key source inputs native-inputs outputs
+                system target
                 (perl (default-perl))
                 #:allow-other-keys
                 #:rest arguments)
@@ -54,6 +55,7 @@
   (and (not target)                               ;XXX: no cross-compilation
        (bag
          (name name)
+         (system system)
          (host-inputs `(,@(if source
                               `(("source" ,source))
                               '())
diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index e28573bb05..3cd537c752 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -93,7 +93,7 @@ prepended to the name."
   (cut package-with-explicit-python <> (default-python2) "python-" "python2-"))
 
 (define* (lower name
-                #:key source inputs native-inputs outputs target
+                #:key source inputs native-inputs outputs system target
                 (python (default-python))
                 #:allow-other-keys
                 #:rest arguments)
@@ -104,6 +104,7 @@ prepended to the name."
   (and (not target)                               ;XXX: no cross-compilation
        (bag
          (name name)
+         (system system)
          (host-inputs `(,@(if source
                               `(("source" ,source))
                               '())
diff --git a/guix/build-system/ruby.scm b/guix/build-system/ruby.scm
index 8312629fd8..e4e115f657 100644
--- a/guix/build-system/ruby.scm
+++ b/guix/build-system/ruby.scm
@@ -35,7 +35,7 @@
     (module-ref ruby 'ruby)))
 
 (define* (lower name
-                #:key source inputs native-inputs outputs target
+                #:key source inputs native-inputs outputs system target
                 (ruby (default-ruby))
                 #:allow-other-keys
                 #:rest arguments)
@@ -46,6 +46,7 @@
   (and (not target)                               ;XXX: no cross-compilation
        (bag
          (name name)
+         (system system)
          (host-inputs `(,@(if source
                               `(("source" ,source))
                               '())
diff --git a/guix/build-system/trivial.scm b/guix/build-system/trivial.scm
index 1b07f14e63..839042aa2a 100644
--- a/guix/build-system/trivial.scm
+++ b/guix/build-system/trivial.scm
@@ -35,11 +35,12 @@
        (package-derivation store guile system)))))
 
 (define* (lower name
-                #:key source inputs native-inputs outputs target
+                #:key source inputs native-inputs outputs system target
                 guile builder modules)
   "Return a bag for NAME."
   (bag
     (name name)
+    (system system)
     (host-inputs `(,@(if source
                          `(("source" ,source))
                          '())