memccpy
end = memccpy(tfmt, fmt, '}', sizeof(tfmt));
void *memccpy(void * __restrict, const void * __restrict, int, size_t);
ATF_CHECK_EQ(memccpy(buf, "foobar", 'r', sizeof(buf)), buf + sizeof("foobar") - 1);
ATF_CHECK_EQ(memccpy(buf, "foobar", mask | 'r', sizeof(buf)), buf + sizeof("foobar") - 1);
memccpy_fn = memccpy;