gnu: guix: Remove the stable-release 'guix' package.

* gnu/packages/package-management.scm (guix-release): Remove.
(guix-devel): Rename to...
(guix): ... this.  Incorporate fields from former 'guix-release'.
(guix-devel): New variable.

gnu/packages/package-management.scm

@@ -68,17 +68,30 @@
                         arch "-linux"
                         "/20131110/guile-2.0.9.tar.xz"))))
 
-(define-public guix-release
+(define-public guix
+  ;; Latest version of Guix, which may or may not correspond to a release.
+  (let ((version "0.12.0")
+        (commit "25a49294caf2386e65fc1b12a2508324be0b1cc2")
+        (revision 9))
     (package
       (name "guix")
-    (version "0.12.0")
+
+      ;; Note: use a very short commit id; with a longer one, the limit on
+      ;; hash-bang lines would be exceeded while running the tests.
+      (version (if (zero? revision)
+                   version
+                   (string-append version "-"
+                                  (number->string revision)
+                                  "." (string-take commit 4))))
       (source (origin
-             (method url-fetch)
-             (uri (string-append "ftp://alpha.gnu.org/gnu/guix/guix-"
-                                 version ".tar.gz"))
+                (method git-fetch)
+                (uri (git-reference
+                      (url "https://git.savannah.gnu.org/r/guix.git")
+                      (commit commit)))
                 (sha256
                  (base32
-               "1jgy5mlygmhxdqhrp6vr8w83ndcm5mk64xfravr8l2d7hq8y40b2"))))
+                  "0p4rh0629j89v4ka5dsp70a1xrfhg7sxjjq54p68vw7x5dkann4a"))
+                (file-name (string-append "guix-" version "-checkout"))))
       (build-system gnu-build-system)
       (arguments
        `(#:configure-flags (list
@@ -89,7 +102,13 @@
                                            "/etc/bash_completion.d")
                             (string-append "--with-libgcrypt-prefix="
                                            (assoc-ref %build-inputs
-                                                    "libgcrypt")))
+                                                      "libgcrypt"))
+
+                            ;; Set 'DOT_USER_PROGRAM' to the empty string so
+                            ;; we don't keep a reference to Graphviz, whose
+                            ;; closure is pretty big (too big for the GuixSD
+                            ;; installation image.)
+                            "ac_cv_path_DOT_USER_PROGRAM=dot")
          #:parallel-tests? #f         ;work around <http://bugs.gnu.org/21097>
 
          #:modules ((guix build gnu-build-system)
@@ -98,6 +117,14 @@
                     (ice-9 rdelim))
 
          #:phases (modify-phases %standard-phases
+                    (add-after 'unpack 'bootstrap
+                      (lambda _
+                        ;; Make sure 'msgmerge' can modify the PO files.
+                        (for-each (lambda (po)
+                                    (chmod po #o666))
+                                  (find-files "." "\\.po$"))
+
+                        (zero? (system* "sh" "bootstrap"))))
                     (add-before
                         'configure 'copy-bootstrap-guile
                       (lambda* (#:key system inputs #:allow-other-keys)
@@ -228,47 +255,10 @@ the usual package management features, it also supports transactional
 upgrades and roll-backs, per-user profiles, and much more.  It is based on
 the Nix package manager.")
       (license gpl3+)
-    (properties '((ftp-server . "alpha.gnu.org")))))
+      (properties '((ftp-server . "alpha.gnu.org"))))))
 
-(define guix-devel
-  ;; Development version of Guix.
-  ;;
-  ;; Note: use a very short commit id; with a longer one, the limit on
-  ;; hash-bang lines would be exceeded while running the tests.
-  (let ((commit "25a49294caf2386e65fc1b12a2508324be0b1cc2"))
-    (package (inherit guix-release)
-      (version (string-append "0.12.0-9." (string-take commit 4)))
-      (source (origin
-                (method git-fetch)
-                (uri (git-reference
-                      ;; "git://git.sv.gnu.org/guix.git" temporarily
-                      ;; unavailable (XXX).
-                      (url "http://git.savannah.gnu.org/r/guix.git")
-                      (commit commit)))
-                (sha256
-                 (base32
-                  "0p4rh0629j89v4ka5dsp70a1xrfhg7sxjjq54p68vw7x5dkann4a"))
-                (file-name (string-append "guix-" version "-checkout"))))
-      (arguments
-       (substitute-keyword-arguments (package-arguments guix-release)
-         ((#:configure-flags flags)
-          ;; Set 'DOT_USER_PROGRAM' to the empty string so we don't keep a
-          ;; reference to Graphviz, whose closure is pretty big (too big for
-          ;; the GuixSD installation image.)
-          `(cons "ac_cv_path_DOT_USER_PROGRAM=dot" ,flags))
-         ((#:phases phases)
-          `(modify-phases ,phases
-             (add-after
-              'unpack 'bootstrap
-              (lambda _
-                ;; Make sure 'msgmerge' can modify the PO files.
-                (for-each (lambda (po)
-                            (chmod po #o666))
-                          (find-files "." "\\.po$"))
-
-                (zero? (system* "sh" "bootstrap")))))))))))
-
-(define-public guix guix-devel)
+;; Alias for backward compatibility.
+(define-public guix-devel guix)
 
 (define (source-file? file stat)
   "Return true if FILE is likely a source file, false if it is a typical