Merge pull request #2933 from cesanta/win_rng

Windows: added alternative to bcrypt lib

mongoose.c

@@ -16388,15 +16388,16 @@ bool mg_random(void *buf, size_t len) {
     success = CryptGenRandom(hProv, len, p);
   }
 #else
-  // BCrypt is a "new generation" strong crypto API, so try it first
-  static BCRYPT_ALG_HANDLE hProv;
-  if (initialised == false &&
-      BCryptOpenAlgorithmProvider(&hProv, BCRYPT_RNG_ALGORITHM, NULL, 0) == 0) {
-    initialised = true;
-  }
-  if (initialised == true) {
-    success = BCryptGenRandom(hProv, p, (ULONG) len, 0) == 0;
+  size_t i;
+  for (i = 0; i < len; i++) {
+    unsigned int rand_v;
+    if (rand_s(&rand_v) == 0) {
+      p[i] = (unsigned char)(rand_v & 255);
+    } else {
+      break;
+    }
   }
+  success = (i == len);
 #endif
 
 #elif MG_ARCH == MG_ARCH_UNIX