stash: refactor stash_create

Refactor the internal stash_create function to use a -m flag for
specifying the message and -u flag to indicate whether untracked files
should be added to the stash.

This makes it easier to pass a pathspec argument to stash_create in the
next patch.

The user interface for git stash create stays the same.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-stash.sh

@@ -58,8 +58,22 @@ clear_stash () {
 }
 
 create_stash () {
-	stash_msg="$1"
-	untracked="$2"
+	stash_msg=
+	untracked=
+	while test $# != 0
+	do
+		case "$1" in
+		-m|--message)
+			shift
+			stash_msg=${1?"BUG: create_stash () -m requires an argument"}
+			;;
+		-u|--include-untracked)
+			shift
+			untracked=${1?"BUG: create_stash () -u requires an argument"}
+			;;
+		esac
+		shift
+	done
 
 	git update-index -q --refresh
 	if no_changes
@@ -268,7 +282,7 @@ push_stash () {
 	git reflog exists $ref_stash ||
 		clear_stash || die "$(gettext "Cannot initialize stash")"
 
-	create_stash "$stash_msg" $untracked
+	create_stash -m "$stash_msg" -u "$untracked"
 	store_stash -m "$stash_msg" -q $w_commit ||
 	die "$(gettext "Cannot save the current status")"
 	say "$(eval_gettext "Saved working directory and index state \$stash_msg")"
@@ -667,7 +681,7 @@ clear)
 	;;
 create)
 	shift
-	create_stash "$*" && echo "$w_commit"
+	create_stash -m "$*" && echo "$w_commit"
 	;;
 store)
 	shift