Use in-house macro `ISALPHA` instead of `isalpha`; ref
@@ -284,7 +284,7 @@ mrb_file_is_absolute_path(const char *path)
{
#ifdef _WIN32
#define IS_PATHSEP(x) (x == '/' || x == '\\')
- if (isalpha(path[0]))
+ if (ISALPHA(path[0]))
return (strlen(path) > 2 && path[1] == ':' && IS_PATHSEP(path[2]));
else
return (IS_PATHSEP(path[0]) && IS_PATHSEP(path[1]));
