am: parse options in stuck-long mode

There is no functional change. The reason for this change is to be able
to add a new option taking an optional argument.

Signed-off-by: Nicolas Vigier <boklm@mars-attacks.org>
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: boklm

git-am.sh

@@ -4,7 +4,7 @@
 
 SUBDIRECTORY_OK=Yes
 OPTIONS_KEEPDASHDASH=
-OPTIONS_STUCKLONG=
+OPTIONS_STUCKLONG=t
 OPTIONS_SPEC="\
 git am [options] [(<mbox>|<Maildir>)...]
 git am [options] (--continue | --skip | --abort)
@@ -414,14 +414,14 @@ it will be removed. Please do not use it anymore."
 		abort=t ;;
 	--rebasing)
 		rebasing=t threeway=t ;;
-	--resolvemsg)
-		shift; resolvemsg=$1 ;;
-	--whitespace|--directory|--exclude|--include)
-		git_apply_opt="$git_apply_opt $(sq "$1=$2")"; shift ;;
-	-C|-p)
-		git_apply_opt="$git_apply_opt $(sq "$1$2")"; shift ;;
-	--patch-format)
-		shift ; patch_format="$1" ;;
+	--resolvemsg=*)
+		resolvemsg="${1#--resolvemsg=}" ;;
+	--whitespace=*|--directory=*|--exclude=*|--include=*)
+		git_apply_opt="$git_apply_opt $(sq "$1")" ;;
+	-C*|-p*)
+		git_apply_opt="$git_apply_opt $(sq "$1")" ;;
+	--patch-format=*)
+		patch_format="${1#--patch-format=}" ;;
 	--reject|--ignore-whitespace|--ignore-space-change)
 		git_apply_opt="$git_apply_opt $1" ;;
 	--committer-date-is-author-date)