submodule-config: make 'config_from_gitmodules' private

Now that 'config_from_gitmodules' is not used in the open, it can be
marked as private.

Hopefully this will prevent its usage for retrieving arbitrary
configuration form the '.gitmodules' file.

Signed-off-by: Antonio Ospite <ao2@ao2.it>
Acked-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

submodule-config.c

@@ -673,14 +673,14 @@ void submodule_free(struct repository *r)
 }
 
 /*
- * Note: This function exists solely to maintain backward compatibility with
- * 'fetch' and 'update_clone' storing configuration in '.gitmodules' and should
- * NOT be used anywhere else.
+ * Note: This function is private for a reason, the '.gitmodules' file should
+ * not be used as as a mechanism to retrieve arbitrary configuration stored in
+ * the repository.
  *
  * Runs the provided config function on the '.gitmodules' file found in the
  * working directory.
  */
-void config_from_gitmodules(config_fn_t fn, void *data)
+static void config_from_gitmodules(config_fn_t fn, void *data)
 {
 	if (the_repository->worktree) {
 		char *file = repo_worktree_path(the_repository, GITMODULES_FILE);

submodule-config.h

@@ -57,15 +57,13 @@ void submodule_free(struct repository *r);
 int check_submodule_name(const char *name);
 
 /*
- * Note: This function exists solely to maintain backward compatibility with
- * 'fetch' and 'update_clone' storing configuration in '.gitmodules' and should
- * NOT be used anywhere else.
+ * Note: these helper functions exist solely to maintain backward
+ * compatibility with 'fetch' and 'update_clone' storing configuration in
+ * '.gitmodules'.
  *
- * Runs the provided config function on the '.gitmodules' file found in the
- * working directory.
+ * New helpers to retrieve arbitrary configuration from the '.gitmodules' file
+ * should NOT be added.
  */
-extern void config_from_gitmodules(config_fn_t fn, void *data);
-
 extern void fetch_config_from_gitmodules(int *max_children, int *recurse_submodules);
 extern void update_clone_config_from_gitmodules(int *max_jobs);