nullptr undeclared identifier when compiling using docker on github codespaces

[mirelle7]

Prerequisites

• I have searched for similar issues and confirmed this is not a duplicate

Game Version

• Command & Conquer Generals
• Command & Conquer Generals: Zero Hour
• Other (please specify below)

Bug Description

The Docker build fails when running in a fresh GitHub Codespace. The error C2065: 'nullptr' : undeclared identifier appears multiple times during compilation.

It seems the recent code updates #1938 introduced nullptr (C++11), which is not supported by the Visual Studio 6 compiler (cl.exe) used in the Docker container.

Expected behavior: The ./scripts/docker-build.sh script should complete successfully as described in the "Quick Start" documentation.

Reproduction Steps

Open https://github.com/TheSuperHackers/GeneralsGameCode
Press on <> Code
Press on Codespaces
Press on +
Wait till the vscode appears
Open terminal

type in: ./scripts/docker-build.sh

error log:
@githubawn ➜ workspacesGeneralsGame.txt

Additional Context

No response

[xezon]

Perhaps docker build is not using precompiled header? It needs to have CppMacros.h in Precompiled header.

Or use C++20.