SDL_utf8strlen: run bit-test explicitly on unsigned char
diff --git a/src/stdlib/SDL_string.c b/src/stdlib/SDL_string.c
index 13d6c54..7a894de 100644
--- a/src/stdlib/SDL_string.c
+++ b/src/stdlib/SDL_string.c
@@ -670,7 +670,7 @@ SDL_utf8strlen(const char *str)
{
size_t retval = 0;
const char *p = str;
- char ch;
+ unsigned char ch;
while ((ch = *(p++)) != 0) {
/* if top two bits are 1 and 0, it's a continuation byte. */