gnu: src: Build from Git.

Upstream's Web server is currently misconfigured to serve:

  content-type: application/x-gzip
  content-encoding: gzip

resulting in an uncompressed tarball on arrival, and a hash mismatch.

The output built from Git is identical to that from the tarball, except
for some insignificant differences in the man page which is now built
from source.

* gnu/packages/version-control.scm (src)[source]: Use GIT-FETCH and
GIT-FILE-NAME.
[native-inputs]: Add asciidoc.

Change-Id: I922055d439057d8fdab48acdc722a55fd43a1dde

gnu/packages/version-control.scm

@@ -3425,13 +3425,15 @@ (define-public src
   (package
     (name "src")
     (version "1.32")
-    (source (origin
-              (method url-fetch)
-              (uri (string-append
-                    "http://www.catb.org/~esr/src/src-" version ".tar.gz"))
-              (sha256
-               (base32
-                "0r9i399kkagpwj08nwf1f7c6lr50xjzzgmzwyjjy6ppgcc53a809"))))
+    (source
+     (origin
+       (method git-fetch)
+       (uri (git-reference
+             (url "https://gitlab.com/esr/src.git/")
+             (commit version)))
+       (file-name (git-file-name name version))
+       (sha256
+        (base32 "0kxbmpjr98kfacjidizxcghl541fwnf8yzfvwfq5f9zbv42p8l41"))))
     (build-system gnu-build-system)
     (arguments
      (list
@@ -3453,8 +3455,10 @@ (define-public src
               (invoke "git" "config" "--global" "user.email" "guix")
               (invoke "./srctest"))))))
     (native-inputs
-     ;; For testing.
-     (list git perl))
+     (list asciidoc
+           ;; For testing.
+           git
+           perl))
     (inputs
      (list bash-minimal
            cssc