Fix an assertion failure triggered by print_otag("sw+-l", NULL).

Even though we skip the style when the argument is NULL,
we must still consume the options.
Not found with afl(1), but during manual testing of the previous patch...

1 files changed, 6 insertions, 1 deletions

diff --git a/html.c b/html.c
index c9c8088e..c3a66b8e 100644
--- a/html.c
+++ b/html.c
@@ -624,8 +624,13 @@ print_otag(struct html *h, enum htmltag tag, const char *fmt, ...)
 			su = va_arg(ap, struct roffsu *);
 			break;
 		case 'w':
-			if ((arg2 = va_arg(ap, char *)) == NULL)
+			if ((arg2 = va_arg(ap, char *)) == NULL) {
+				if (*fmt == '+')
+					fmt++;
+				if (*fmt == '-')
+					fmt++;
 				break;
+			}
 			su = &mysu;
 			a2width(arg2, su);
 			if (*fmt == '+') {