Add a "fork" of musl as //fusl.

fusl/src/prng/random.c

+#include <stdlib.h>
+#include <stdint.h>
+#include "libc.h"
+
+/*
+this code uses the same lagged fibonacci generator as the
+original bsd random implementation except for the seeding
+which was broken in the original
+*/
+
+static uint32_t init[] = {
+0x00000000,0x5851f42d,0xc0b18ccf,0xcbb5f646,
+0xc7033129,0x30705b04,0x20fd5db4,0x9a8b7f78,
+0x502959d8,0xab894868,0x6c0356a7,0x88cdb7ff,
+0xb477d43f,0x70a3a52b,0xa8e4baf1,0xfd8341fc,
+0x8ae16fd9,0x742d2f7a,0x0d1f0796,0x76035e09,
+0x40f7702c,0x6fa72ca5,0xaaa84157,0x58a0df74,
+0xc74a0364,0xae533cc4,0x04185faf,0x6de3b115,
+0x0cab8628,0xf043bfa4,0x398150e9,0x37521657};
+
+static int n = 31;
+static int i = 3;
+static int j = 0;
+static uint32_t *x = init+1;
+static volatile int lock[2];
+
+static uint32_t lcg31(uint32_t x) {
+        return (1103515245*x + 12345) & 0x7fffffff;
+}
+
+static uint64_t lcg64(uint64_t x) {
+        return 6364136223846793005ull*x + 1;
+}
+
+static void *savestate() {
+        x[-1] = (n<<16)|(i<<8)|j;
+        return x-1;
+}
+
+static void loadstate(uint32_t *state) {
+        x = state+1;
+        n = x[-1]>>16;
+        i = (x[-1]>>8)&0xff;
+        j = x[-1]&0xff;
+}
+
+static void __srandom(unsigned seed) {
+        int k;
+        uint64_t s = seed;
+
+        if (n == 0) {
+                x[0] = s;
+                return;
+        }
+        i = n == 31 || n == 7 ? 3 : 1;
+        j = 0;
+        for (k = 0; k < n; k++) {
+                s = lcg64(s);
+                x[k] = s>>32;
+        }
+        /* make sure x contains at least one odd number */
+        x[0] |= 1;
+}
+
+void srandom(unsigned seed) {
+        LOCK(lock);
+        __srandom(seed);
+        UNLOCK(lock);
+}
+
+char *initstate(unsigned seed, char *state, size_t size) {
+        void *old;
+
+        if (size < 8)
+                return 0;
+        LOCK(lock);
+        old = savestate();
+        if (size < 32)
+                n = 0;
+        else if (size < 64)
+                n = 7;
+        else if (size < 128)
+                n = 15;
+        else if (size < 256)
+                n = 31;
+        else
+                n = 63;
+        x = (uint32_t*)state + 1;
+        __srandom(seed);
+        savestate();
+        UNLOCK(lock);
+        return old;
+}
+
+char *setstate(char *state) {
+        void *old;
+
+        LOCK(lock);
+        old = savestate();
+        loadstate((uint32_t*)state);
+        UNLOCK(lock);
+        return old;
+}
+
+long random(void) {
+        long k;
+
+        LOCK(lock);
+        if (n == 0) {
+                k = x[0] = lcg31(x[0]);
+                goto end;
+        }
+        x[i] += x[j];
+        k = x[i]>>1;
+        if (++i == n)
+                i = 0;
+        if (++j == n)
+                j = 0;
+end:
+        UNLOCK(lock);
+        return k;
+}