build: Produce (guix config) instead of using compile-time tricks.

* guix/config.scm.in: New file.
* guix/utils.scm: Use it.
  (%libgcrypt): Remove.
  (%nixpkgs-directory): Don't capture the compile-time $NIXPKGS; use
  %NIXPKGS instead.
  (nixpkgs-derivation): Use %NIX-INSTANTIATE.
* pre-inst-env.in (NIX_INSTANTIATE, NIXPKGS, LIBGCRYPT): Remove.

* configure.ac: Emit `guix/config.scm'.
* Makefile.am (GOBJECTS): Add `guix/config.go'.
  (nobase_nodist_guilemodule_DATA): Add `guix/config.scm'.

2 files changed, 56 insertions, 7 deletions

diff --git a/guix/config.scm.in b/guix/config.scm.in
new file mode 100644
index 0000000000..462dcd0ed1
--- /dev/null
+++ b/guix/config.scm.in
@@ -0,0 +1,53 @@
+;;; Guix --- Nix package management from Guile.         -*- coding: utf-8 -*-
+;;; Copyright (C) 2012 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of Guix.
+;;;
+;;; Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with Guix.  If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (guix config)
+  #:export (%guix-package-name
+            %guix-version
+            %guix-bug-report-address
+            %libgcrypt
+            %nixpkgs
+            %nix-instantiate))
+
+;;; Commentary:
+;;;
+;;; Compile-time configuration of Guix.
+;;;
+;;; Code:
+
+(define %guix-package-name
+  "@PACKAGE_NAME@")
+
+(define %guix-version
+  "@PACKAGE_VERSION@")
+
+(define %guix-bug-report-address
+  "@PACKAGE_BUGREPORT@")
+
+(define %libgcrypt
+  "@LIBGCRYPT@")
+
+(define %nixpkgs
+  (if (string=? "@NIXPKGS@" "")
+      #f
+      "@NIXPKGS@"))
+
+(define %nix-instantiate
+  "@NIX_INSTANTIATE@")
+
+;;; config.scm ends here
diff --git a/guix/utils.scm b/guix/utils.scm
index 287a6d4f3a..10b0c15fad 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -17,6 +17,7 @@
 ;;; along with Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix utils)
+  #:use-module (guix config)
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-26)
@@ -392,10 +393,6 @@ starting from the right of S."
 ;;; Hash.
 ;;;
 
-(define %libgcrypt
-  ;; Name of the libgcrypt shared library.
-  (compile-time-value (or (getenv "LIBGCRYPT") "libgcrypt")))
-
 (define sha256
   (cond
    ((compile-time-value
@@ -458,13 +455,12 @@ starting from the right of S."
 (define %nixpkgs-directory
   (make-parameter
    ;; Capture the build-time value of $NIXPKGS.
-   (or (compile-time-value (getenv "NIXPKGS"))
-       (getenv "NIXPKGS"))))
+   (or %nixpkgs (getenv "NIXPKGS"))))
 
 (define* (nixpkgs-derivation attribute #:optional (system (%current-system)))
   "Return the derivation path of ATTRIBUTE in Nixpkgs."
   (let* ((p (open-pipe* OPEN_READ (or (getenv "NIX_INSTANTIATE")
-                                      "nix-instantiate")
+                                      %nix-instantiate)
                         "-A" attribute (%nixpkgs-directory)
                         "--argstr" "system" system))
          (l (read-line p))