Compiling mujoco with MinGW fails because of redefined stat

[maximilian-maisel-bl]

Intro

I'm compiling Mujoco for different targets in a Linux-based CI.

My setup

• Ubuntu 24.04 amd64
• Mujoco 3.4.0

What's happening? What did you expect?

Building Mujoco with MinGW fails because stat is redefined.

[  9%] Building CXX object CMakeFiles/mujoco.dir/src/user/user_resource.cc.obj
/home/user/mujoco/src/user/user_resource.cc:36: error: "stat" redefined [-Werror]
   36 |   #define stat _stat
      | 
In file included from /home/user/mujoco/src/user/user_resource.cc:19:
/usr/share/mingw-w64/include/sys/stat.h:279: note: this is the location of the previous definition
  279 | #define stat _stat64
      | 
cc1plus: all warnings being treated as errors

I'd expect that it compiles without errors. This used to work with Mujoco 3.3.3.

As a workaround, I can comment out the define in line 36.

Steps for reproduction

• Building Mujoco with mingw:
  cmake -DCMAKE_TOOLCHAIN_FILE=~/cmake-toolchain-mingw64-x86_64.cmake -DCMAKE_COMPILE_WARNING_AS_ERROR=false ..
• Remove problematic section from mujoco.rc file (Issue Build fails with gcc and mingw makefiles : Syntax Error #839)
• Workaround localtime issue Compiling mujoco with MinGW fails because of thread-safe localtime #3037
• Run make

This is the content of the toolchain file:

set(CMAKE_SYSTEM_NAME Windows)
set(CMAKE_SYSTEM_PROCESSOR x86_64)

find_program(CMAKE_C_LINKER NAMES x86_64-w64-mingw32-ld)
find_program(CMAKE_C_COMPILER NAMES x86_64-w64-mingw32-gcc)
find_program(CMAKE_CXX_COMPILER NAMES x86_64-w64-mingw32-g++)

### Minimal model for reproduction

This bug is independent of the model and code.

### Code required for reproduction

This bug is independent of the model and code.

### Confirmations

- [x] I searched the [latest documentation](https://mujoco.readthedocs.io/en/latest/overview.html) thoroughly before posting.
- [x] I searched previous [Issues](https://github.com/google-deepmind/mujoco/issues) and [Discussions](https://github.com/google-deepmind/mujoco/discussions), I am certain this has not been raised before.