[PROTON-2786] Cannot cross-compile proton-c using the `zig c++` compiler

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: proton-c-0.39.0
• Fix Version/s: proton-c-0.40.0
• Component/s: build
• Assignee: Jiri Daněk
• Reporter: Jiri Daněk
• Created: 22/Dec/23 15:52
• Updated: 24/Dec/23 19:28
• Resolved: 24/Dec/23 19:28

Description

Cross-compiling with `zig cc`/`zig c++` is a very useful feature.

Here are some references how it works and why it is so nice

1. https://ziglang.org/learn/overview/#cross-compiling-is-a-first-class-use-case
2. https://andrewkelley.me/post/zig-cc-powerful-drop-in-replacement-gcc-clang.html
3. https://jakstys.lt/2022/how-uber-uses-zig/
4. https://www.uber.com/en-CZ/blog/bootstrapping-ubers-infrastructure-on-arm64-with-zig/
5. https://www.youtube.com/watch?v=SCj2J3HcEfc

What currently happens when compiling with CXX='zig c++' is the following

    Building CXX object CMakeFiles/cmTC_44138.dir/testCXXCompiler.cxx.o
    /usr/local/bin/zig    -o CMakeFiles/cmTC_44138.dir/testCXXCompiler.cxx.o -c /build/proton/app/build/CMakeFiles/CMakeTmp/testCXXCompiler.cxx
    info: Usage: zig [command] [options]

That is, it drops the `c+` part of the command line. This seems to happen when compiling proton-c in the check for a working C+ compiler (to optionally enable tests in C++)

Issue Links

• links to: `check_language(lang)` drops `CMAKE_${lang}_COMPILER_ARG1`