ref: 7b8f9336dd0170c6dcaf12368b0c03c8019c5ab5
dir: /lib/c/memcmp.c/
#include <string.h>
#undef memcmp
int
memcmp(const void *s1, const void *s2, size_t n)
{
const char *s = s1;
const char *t = s2;
for ( ; n > 0 && *s == *t; --n)
++s, ++t;
return (n > 0) ? *(unsigned char *) s - *(unsigned char *) t : 0;
}