Merge branch 'jc/fix-diff-no-index-diff-opt-parse'

"diff --no-index -Mq a b" fell into an infinite loop.

* jc/fix-diff-no-index-diff-opt-parse:
  diff-no-index: correctly diagnose error return from diff_opt_parse()

Author: gitster

diff-no-index.c

@@ -198,7 +198,7 @@ void diff_no_index(struct rev_info *revs,
 			i++;
 		else {
 			j = diff_opt_parse(&revs->diffopt, argv + i, argc - i);
-			if (!j)
+			if (j <= 0)
 				die("invalid diff option/value: %s", argv[i]);
 			i += j;
 		}