build-system: Factorize the list of modules imported on the build side.

* guix/build-system/gnu.scm (%default-modules): Rename to...
  (%gnu-build-system-modules): ... this.
  (%default-modules): New variable.
  (dist-package, gnu-build): Use %GNU-BUILD-SYSTEM-MODULES for
  #:imported-modules.
  (gnu-cross-build): Likewise, and use %DEFAULT-MODULES for #:modules.
* guix/build-system/cmake.scm (%cmake-build-system-modules): New
  variable.
  (cmake-build): Use it for #:imported-modules.
* guix/build-system/glib-or-gtk.scm (%default-imported-modules): Rename
  to...
  (%glib-or-gtk-build-system-modules): ... this.  Refer to
  %GNU-BUILD-SYSTEM-MODULES.  Adjust uses.
* guix/build-system/perl.scm (%perl-build-system-modules): New
  variable.
  (perl-build): Use it for #:imported-modules.
* guix/build-system/python.scm (%python-build-system-modules): New
  variable.
  (python-build): Use it for #:imported-modules.
* guix/build-system/ruby.scm (%ruby-build-system-modules): New variable.
  (ruby-build): Use it for #:imported-modules.
* guix/build-system/waf.scm (%waf-build-system-modules): New variable.
  (waf-build): Use it for #:imported-modules.

1 files changed, 8 insertions, 4 deletions

diff --git a/guix/build-system/python.scm b/guix/build-system/python.scm
index 37108650d0..d498cf618b 100644
--- a/guix/build-system/python.scm
+++ b/guix/build-system/python.scm
@@ -27,7 +27,8 @@
   #:use-module (guix build-system gnu)
   #:use-module (ice-9 match)
   #:use-module (srfi srfi-26)
-  #:export (package-with-python2
+  #:export (%python-build-system-modules
+            package-with-python2
             python-build
             python-build-system))
 
@@ -38,6 +39,11 @@
 ;;
 ;; Code:
 
+(define %python-build-system-modules
+  ;; Build-side modules imported by default.
+  `((guix build python-build-system)
+    ,@%gnu-build-system-modules))
+
 (define (default-python)
   "Return the default Python package."
   ;; Lazily resolve the binding to avoid a circular dependency.
@@ -132,9 +138,7 @@ prepended to the name."
                        (search-paths '())
                        (system (%current-system))
                        (guile #f)
-                       (imported-modules '((guix build python-build-system)
-                                           (guix build gnu-build-system)
-                                           (guix build utils)))
+                       (imported-modules %python-build-system-modules)
                        (modules '((guix build python-build-system)
                                   (guix build utils))))
   "Build SOURCE using PYTHON, and with INPUTS.  This assumes that SOURCE