Merge branch 'nd/diff-parseopt'

A brown-paper-bag bugfix to a change already in 'master'.

* nd/diff-parseopt:
  parse-options: check empty value in OPT_INTEGER and OPT_ABBREV
  diff-parseopt: restore -U (no argument) behavior
  diff-parseopt: correct variable types that are used by parseopt

diff.h

@@ -169,7 +169,7 @@ struct diff_options {
 	const char *prefix;
 	int prefix_length;
 	const char *stat_sep;
-	long xdl_opts;
+	int xdl_opts;
 
 	/* see Documentation/diff-options.txt */
 	char **anchors;