git-authenticate, inferior: Autoload Git modules.

The primary motivation is that, since (guix git-authenticate) is part of
the (guix describe) closure and might thus end up on the build side,
autoloading allows us to not add a ‘with-extensions’ stanza for Guile-Git to
every gexp that pulls in (guix describe).

This situation happens with (guix platform) in the following commit.

* guix/git-authenticate.scm: Explicitly autoload (git …) modules and (guix
git).
* guix/inferior.scm: Autoload (guix git).

Change-Id: Ie26f302cd88603d2d787048213864013bfff572f
Signed-off-by: Ludovic Courtès <ludo@gnu.org>

guix/git-authenticate.scm

@@ -17,14 +17,29 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (guix git-authenticate)
-  #:use-module (git)
+  #:autoload   (git oid) (oid->string
+                          string->oid)
+  #:autoload   (git blob) (blob-lookup blob-content)
+  #:autoload   (git branch) (branch-lookup BRANCH-ALL)
+  #:autoload   (git commit) (commit-lookup
+                             commit-parents
+                             commit-id
+                             commit-tree
+                             commit-extract-signature)
+  #:autoload   (git errors) (GIT_ENOTFOUND)
+  #:autoload   (git reference) (reference-target)
+  #:autoload   (git repository) (repository-directory repository-head)
+  #:autoload   (git structs) (git-error-code)
+  #:autoload   (git tree) (tree-entry-bypath
+                           tree-list
+                           tree-entry-id
+                           tree-entry-name)
   #:autoload   (gcrypt hash) (sha256)
   #:use-module (guix base16)
   #:autoload   (guix base64) (base64-encode)
-  #:use-module ((guix git)
-                #:select (commit-difference
-                          commit-descendant?
-                          false-if-git-not-found))
+  #:autoload   (guix git) (commit-difference
+                           commit-descendant?
+                           false-if-git-not-found)
   #:use-module (guix i18n)
   #:use-module ((guix diagnostics) #:select (formatted-message))
   #:use-module (guix openpgp)

guix/inferior.scm

@@ -40,7 +40,7 @@
   #:use-module (guix search-paths)
   #:use-module (guix profiles)
   #:use-module (guix channels)
-  #:use-module ((guix git) #:select (update-cached-checkout commit-id?))
+  #:autoload   (guix git) (update-cached-checkout commit-id?)
   #:use-module (guix monads)
   #:use-module (guix store)
   #:use-module (guix derivations)