Windows: use CPU RDRAND or RDSEED as an additional entropy source for our random generator when available

src/Crypto/rdrand.h

@@ -0,0 +1,26 @@
+#ifndef HEADER_Crypto_RDRAND
+#define HEADER_Crypto_RDRAND
+
+#include "Common/Tcdefs.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * generate bufLen random bytes using CPU RDRAND instruction
+ * return 1 in case of success and 0 in case of failure
+ */
+int RDRAND_getBytes(unsigned char* buf, size_t bufLen);
+
+/*
+ * generate bufLen random bytes using CPU RDSEED instruction
+ * return 1 in case of success and 0 in case of failure
+ */
+int RDSEED_getBytes(unsigned char* buf, size_t bufLen);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif