Merge branch 'fg/submodule-git-file-git-dir'

* fg/submodule-git-file-git-dir:
  Move git-dir for submodules
  rev-parse: add option --resolve-git-dir <path>

Conflicts:
	cache.h
	git-submodule.sh

setup.c

@@ -812,3 +812,10 @@ const char *setup_git_directory(void)
 {
 	return setup_git_directory_gently(NULL);
 }
+
+const char *resolve_gitdir(const char *suspect)
+{
+	if (is_git_directory(suspect))
+		return suspect;
+	return read_gitfile(suspect);
+}