Avoid ctype warnings.

diff --git a/test_utils/test_main.c b/test_utils/test_main.c
index 20ce551828ca7bcd4e4c44e041df2ba6215fa46b..2ff942c84a44d92d3dda6a7b3665710d4d2aa223 100644 (file)
--- a/test_utils/test_main.c
+++ b/test_utils/test_main.c
@@ -2166,7 +2166,7 @@ void assertVersion(const char *prog, const char *base)
 
        /* Skip arbitrary third-party version numbers. */
        while (s > 0 && (*q == ' ' || *q == '-' || *q == '/' || *q == '.' ||
-           isalnum(*q))) {
+           isalnum((unsigned char)*q))) {
                ++q;
                --s;
        }