Change default store values from /nix/store to /gnu/store.

* gnu/packages/ld-wrapper.scm (%store-directory): Change the default to
  /gnu/store.
* guix/build/utils.scm (%store-directory): New procedure.
  (remove-store-references): Use it for the default value of 'store'.
* guix/packages.scm (patch-and-repack)[builder]: Change default store to
  /gnu/store.

gnu/packages/ld-wrapper.scm

@@ -11,7 +11,7 @@ main="(@ (gnu build-support ld-wrapper) ld-wrapper)"
 exec @GUILE@ -c "(load-compiled \"$0.go\") (apply $main (cdr (command-line)))" "$@"
 !#
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -63,7 +63,7 @@ exec @GUILE@ -c "(load-compiled \"$0.go\") (apply $main (cdr (command-line)))" "
 
 (define %store-directory
   ;; File name of the store.
-  (or (getenv "NIX_STORE") "/nix/store"))
+  (or (getenv "NIX_STORE") "/gnu/store"))
 
 (define %temporary-directory
   ;; Temporary directory.

guix/build/utils.scm

@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2012, 2013 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2012, 2013, 2014 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2013 Andreas Enge <andreas@enge.fr>
 ;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org>
 ;;;
@@ -29,7 +29,8 @@
   #:use-module (rnrs io ports)
   #:re-export (alist-cons
                alist-delete)
-  #:export (directory-exists?
+  #:export (%store-directory
+            directory-exists?
             executable-file?
             call-with-ascii-input-file
             with-directory-excursion
@@ -62,6 +63,11 @@
 ;;; Directories.
 ;;;
 
+(define (%store-directory)
+  "Return the directory name of the store."
+  (or (getenv "NIX_STORE")
+      "/gnu/store"))
+
 (define (directory-exists? dir)
   "Return #t if DIR exists and is a directory."
   (let ((s (stat dir #f)))
@@ -443,7 +449,7 @@ all subject to the substitutions."
 
 
 ;;;
-;;; Patching shebangs---e.g., /bin/sh -> /nix/store/xyz...-bash/bin/sh.
+;;; Patching shebangs---e.g., /bin/sh -> /gnu/store/xyz...-bash/bin/sh.
 ;;;
 
 (define* (dump-port in out
@@ -630,8 +636,7 @@ for each unmatched character."
                    (unmatched (car matched) result)))))))
 
 (define* (remove-store-references file
-                                  #:optional (store (or (getenv "NIX_STORE")
-                                                        "/nix/store")))
+                                  #:optional (store (%store-directory)))
   "Remove from FILE occurrences of file names in STORE; return #t when
 store paths were encountered in FILE, #f otherwise.  This procedure is
 known as `nuke-refs' in Nixpkgs."

guix/packages.scm

@@ -368,8 +368,7 @@ IMPORTED-MODULES specify modules to use/import for use by SNIPPET."
 
          ;; SOURCE may be either a directory or a tarball.
          (and (if (file-is-directory? source)
-                  (let* ((store      (or (getenv "NIX_STORE")
-                                         "/nix/store"))
+                  (let* ((store     (or (getenv "NIX_STORE") "/gnu/store"))
                          (len       (+ 1 (string-length store)))
                          (base      (string-drop source len))
                          (dash      (string-index base #\-))