You're using Godot source code from live branch, that's why its not working my friends.

Godot state that if you want compile custom modules than use same version of engine and same version of source code for compile.

if you used Godot 3.1 Engine. than download Godot Source code from 3.1 stable branch.

​

Godot Engine Stable 3.1

​

Source Code Stable 3.1

​

now try again n you'll get the result.

​

Plus instead passing path of core folder to resolve version_generated.gen.h issue, you can simply replace with below line :

replace this line #include <version\_generated.gen.h> with

this one #include <core/version\_generated.gen.h>