self: Shrink the module search path of the 'guix' command.

Previously we'd have lots of useless entries on the search paths, such
as libtasn1, libidn2, zlib, gmp, etc. because they are propagated by
gnutls.

* guix/self.scm (guix-command)[source-directories, object-directories]:
New variables.  Use them in the body of "guix-command".  Filter their
items with 'file-exists?'.

diff --git a/guix/self.scm b/guix/self.scm
index 5ad644b..90649db 100644 (file)
--- a/guix/self.scm
+++ b/guix/self.scm
@@ -367,22 +367,26 @@ DOMAIN, a gettext domain."
                        guile (guile-version (effective-version)))
   "Return the 'guix' command such that it adds MODULES and DEPENDENCIES in its
 load path."
+  (define source-directories
+    (map (lambda (package)
+           (file-append package "/share/guile/site/"
+                        guile-version))
+         dependencies))
+
+  (define object-directories
+    (map (lambda (package)
+           (file-append package "/lib/guile/"
+                        guile-version "/site-ccache"))
+         dependencies))
+
   (program-file "guix-command"
                 #~(begin
                     (set! %load-path
-                      (append '#$(map (lambda (package)
-                                        (file-append package
-                                                     "/share/guile/site/"
-                                                     guile-version))
-                                      dependencies)
+                      (append (filter file-exists? '#$source-directories)
                               %load-path))
 
                     (set! %load-compiled-path
-                      (append '#$(map (lambda (package)
-                                        (file-append package "/lib/guile/"
-                                                     guile-version
-                                                     "/site-ccache"))
-                                      dependencies)
+                      (append (filter file-exists? '#$object-directories)
                               %load-compiled-path))
 
                     (set! %load-path (cons #$modules %load-path))