Added getentropy() support.

Prodded by David Carlier.

src/nxt_random.c

@@ -68,6 +68,14 @@ nxt_random_stir(nxt_random_t *r)
 
     n = syscall(SYS_getrandom, &key, NXT_RANDOM_KEY_SIZE, 0);
 
+#elif (NXT_HAVE_GETENTROPY || NXT_HAVE_GETENTROPY_SYS_RANDOM)
+
+    n = 0;
+
+    if (getentropy(&key, NXT_RANDOM_KEY_SIZE) == 0) {
+        n = NXT_RANDOM_KEY_SIZE;
+    }
+
 #else
 
     n = 0;

src/nxt_unix.h

@@ -234,6 +234,8 @@
 #include <sys/random.h>             /* getrandom(). */
 #elif (NXT_HAVE_LINUX_SYS_GETRANDOM)
 #include <linux/random.h>           /* SYS_getrandom. */
+#elif (NXT_HAVE_GETENTROPY_SYS_RANDOM)
+#include <sys/random.h>             /* getentropy(). */
 #endif