Teach git-bundle to read revision arguments from stdin like git-rev-list.

This patch allows the caller to feed the revision parameters to git-bundle
from its standard input.  This way, a script do not have to worry about
limitation of the length of command line.

Documentation/git-bundle.txt says that git-bundle takes arguments acceptable
to git-rev-list.  Obviously some arguments that git-rev-list handles don't
make sense for git-bundle (e.g. --bisect) but --stdin is pretty reasonable.

Signed-off-by: Adam Brewster <adambrewster@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bundle.c

@@ -178,6 +178,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 	int i, ref_count = 0;
 	char buffer[1024];
 	struct rev_info revs;
+	int read_from_stdin = 0;
 	struct child_process rls;
 	FILE *rls_fout;
 
@@ -227,8 +228,16 @@ int create_bundle(struct bundle_header *header, const char *path,
 
 	/* write references */
 	argc = setup_revisions(argc, argv, &revs, NULL);
-	if (argc > 1)
-		return error("unrecognized argument: %s'", argv[1]);
+
+	for (i = 1; i < argc; i++) {
+		if (!strcmp(argv[i], "--stdin")) {
+			if (read_from_stdin++)
+				die("--stdin given twice?");
+			read_revisions_from_stdin(&revs);
+			continue;
+		}
+		return error("unrecognized argument: %s'", argv[i]);
+	}
 
 	for (i = 0; i < revs.pending.nr; i++) {
 		struct object_array_entry *e = revs.pending.objects + i;