Merge branch 'jk/diff-submodule-diff-inline'

"git diff --submodule=diff" now recurses into nested submodules.

* jk/diff-submodule-diff-inline:
  diff: recurse into nested submodules for inline diff

submodule.c

@@ -554,7 +554,8 @@ void show_submodule_inline_diff(FILE *f, const char *path,
 	cp.no_stdin = 1;
 
 	/* TODO: other options may need to be passed here. */
-	argv_array_push(&cp.args, "diff");
+	argv_array_pushl(&cp.args, "diff", "--submodule=diff", NULL);
+
 	argv_array_pushf(&cp.args, "--line-prefix=%s", line_prefix);
 	if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 		argv_array_pushf(&cp.args, "--src-prefix=%s%s/",