Run `X:\gta5\src\dev_ng\game\VS_Project\load_sln_unity_2012.bat` and press Enter when you see WARNING.
If prompted with “How do you want to open this file?”, check “Always use this app to open .sln files” and click OK.
Once the solution loads, open the dropdown menu that says “Debug” at the top, select “Configuration Manager.”
Change “Active Solution Platform” to “x64” and close the configuration window.
Hold Ctrl key and click all projects under “GameLibs” and “Rage,” right-click and select “Properties.”
In the “Configuration” dropdown, select “All Configurations.” Select `C/C++ > All options`, under “Look for options or switches,” search “err” and set “Treat Warnings as Errors” to “No (/WX-)”, then click “Apply” and “OK.” For faster compiles, search “mul” and set “Multiprocessor Compilation” to “Yes (/MP).”
Right-click the “game” project and select “Properties” and do step 5 again.
At the top of the window, select `Build > Build Solution` and wait for the build to finish.
Copy output binary to the game folder, make sure to overwrite the existing binary.