Enable /WX, warning as error on Visual Studio

test/core/core_func_noise.cpp

@@ -1,22 +1,7 @@
-struct vec4
-{
-	static int length();
-};
-
-int vec4::length()
-{
-	return 4;
-}
-
 int main()
 {
-	int Failed = 0;
+	int Error = 0;
 
-	vec4 V;
-
-	int LengthA = V.length();
-	int LengthB = vec4::length();
-
-	return Failed;
+	return Error;
 }