Often I need to generate random unsigned integers for seeding PRNGs. The best way is using the getentropy() system function to read OS level randomness into your array.

#include <sys/random.h>

// Read from system random to fill up data structure
int8_t fill_urandom(void *buf, size_t bytes) {
    int8_t ok = getentropy(buf, bytes);

    return (ok == 0);
}

Declare your array of integers, and then pass it as a pointer to this function to fill with random bytes from your OS. This will get you a bunch of random integers you can use for seeding PRNGs.

uint64_t seed[4];
fill_urandom(seed, sizeof(seed));