Added rand_bytes for Windows in core:crypto

core/crypto/rand_generic.odin

@@ -1,6 +1,6 @@
 package crypto
 
-when ODIN_OS != .Linux && ODIN_OS != .OpenBSD {
+when ODIN_OS != .Linux && ODIN_OS != .OpenBSD && ODIN_OS != .Windows {
 	_rand_bytes :: proc (dst: []byte) {
 		unimplemented("crypto: rand_bytes not supported on this OS")
 	}

core/crypto/rand_windows.odin

@@ -0,0 +1,23 @@
+package crypto
+
+import win32 "core:sys/windows"
+import "core:os"
+import "core:fmt"
+
+_rand_bytes :: proc(dst: []byte) {
+	ret := (os.Errno)(win32.BCryptGenRandom(nil, raw_data(dst), u32(len(dst)), win32.BCRYPT_USE_SYSTEM_PREFERRED_RNG))
+	if ret != os.ERROR_NONE {
+		switch ret {
+			case os.ERROR_INVALID_HANDLE:
+				// The handle to the first parameter is invalid.
+				// This should not happen here, since we explicitly pass nil to it
+				panic("crypto: BCryptGenRandom Invalid handle for hAlgorithm")
+			case os.ERROR_INVALID_PARAMETER:
+				// One of the parameters was invalid
+				panic("crypto: BCryptGenRandom Invalid parameter")
+			case:
+				// Unknown error
+				panic(fmt.tprintf("crypto: BCryptGenRandom failed: %d\n", ret))
+		}
+	}
+}