Add explicit type cast to return value from `mrmchr`; ref
C++ is stricter in implicit type casting.
@@ -516,7 +516,7 @@ mrb_memsearch_qs(const unsigned char *xs, mrb_int m, const unsigned char *ys, mr
const unsigned char *ye = ys+n-m+1;
for (;;) {
- y = memchr(y, xs[0], (size_t)(ye-y));
+ y = (const unsigned char*)memchr(y, xs[0], (size_t)(ye-y));
if (y == NULL) return -1;
if (memcmp(xs, y, m) == 0) {
return (mrb_int)(y - ys);
