gnu: guile-emacs: Fetch source over HTTPS and be more idiomatic.

Fixes <https://bugs.gnu.org/27795>.

* gnu/packages/emacs.scm (guile-emacs)[source]: Use HTTPS.
Use git-version and git-file-name.

gnu/packages/emacs.scm

@@ -254,15 +254,17 @@ editor (without an X toolkit)" )
                        (package-arguments emacs)))))
 
 (define-public guile-emacs
+  (let ((commit "41120e0f595b16387eebfbf731fff70481de1b4b")
+        (revision "0"))
     (package (inherit emacs)
       (name "guile-emacs")
-    (version "20150512.41120e0")
+      (version (git-version "0.0.0" revision commit))
       (source (origin
                 (method git-fetch)
                 (uri (git-reference
-                    (url "git://git.hcoop.net/git/bpt/emacs.git")
+                      (url "https://git.hcoop.net/git/bpt/emacs.git")
-                    (commit "41120e0f595b16387eebfbf731fff70481de1b4b")))
+                      (commit commit)))
-              (file-name (string-append name "-" version "-checkout"))
+                (file-name (git-file-name name version))
                 (patches (search-patches "guile-emacs-fix-configure.patch"))
                 (sha256
                  (base32
@@ -286,7 +288,7 @@ editor (without an X toolkit)" )
              ;; Build sometimes fails: deps/dispnew.d: No such file or directory
              (add-before 'build 'make-deps-dir
                (lambda _
-               (invoke "mkdir" "-p" "src/deps")))))))))
+                 (invoke "mkdir" "-p" "src/deps"))))))))))
 
 (define-public m17n-db
   (package