1 files changed, 2 insertions, 2 deletions
diff --git a/regex.c b/regex.c
index 193e10f667..9e64af57d1 100644
--- a/regex.c
+++ b/regex.c
@@ -1011,8 +1011,8 @@ calculate_must_string(start, end)
 {
   int mcnt;
   int max = 0;
-  char *p = start;
-  char *pend = end;
+  unsigned char *p = start;
+  unsigned char *pend = end;
   char *must = 0;
 
   if (start == NULL) return 0;