ref: b02b5fd160095f12c706e8b731bcc1feb6855d58
dir: /src/libc/string/memchr.c/
#include <string.h>
#undef memchr
void *
memchr(const void *s, int c, size_t n)
{
unsigned char *bp = (unsigned char *) s;
while (n > 0 && *bp++ != c)
--n;
return (n == 0) ? NULL : bp-1;
}