I just hate to be pushed around by some @#$%^& machine.
diff --git a/src/cmd/calendar.c b/src/cmd/calendar.c
index ba86ab3..778c760 100644
--- a/src/cmd/calendar.c
+++ b/src/cmd/calendar.c
@@ -174,7 +174,7 @@
 upper2lower(char *to, char *from, int len)
 {
 	while(--len>0 && *from!='\0')
-		*to++ = tolower(*from++);
+		*to++ = tolower((uchar)*from++);
 	*to = 0;
 }