Cast signed chars before ctype calls

A plain char is undefined in the ctype functions for negative values,
which a high byte produces wherever char is signed.

1 file changed, 1 insertion, 1 deletion

diff --git a/source/ui-clone.c b/source/ui-clone.c
index e11f496..c554c24 100644
--- a/source/ui-clone.c
+++ b/source/ui-clone.c
@@ -115,7 +115,7 @@ void cgit_clone_objects(void)
 	for (p = ctx.qry.path; *p; ++p) {
 		if (*p == '.' && *(p + 1) == '.')
 			goto err;
-		if (!isalnum(*p) && *p != '/' && *p != '.' && *p != '-')
+		if (!isalnum((unsigned char)*p) && *p != '/' && *p != '.' && *p != '-')
 			goto err;
 	}