Empty conditions count as false.

When negated, they still count as false.
Found when investigating crashes jsg@ found with afl.
Not completely fixing the crashes yet.

1 files changed, 2 insertions, 0 deletions

diff --git a/roff.c b/roff.c
index 08a4f922..32cc6c31 100644
--- a/roff.c
+++ b/roff.c
@@ -1258,6 +1258,8 @@ roff_evalcond(struct roff *r, int ln, const char *v, int *pos)
 		wanttrue = 1;
 
 	switch (v[*pos]) {
+	case '\0':
+		return(0);
 	case 'n':
 		/* FALLTHROUGH */
 	case 'o':