luarocks: fails to install Lua modules written in C on CLANG64 and CLANGARM64

[luau-project]

Description / Steps to reproduce the issue

In the current LuaRocks setup for CLANG64 and CLANGARM64, the default configuration has a fallback to use gcc as standard C compiler when the CC environment variable is not set. This configuration makes the building of any Lua module with parts written in C to fail, because LuaRocks tries to use gcc rather than clang.

To reproduce this issue, make sure that: 1) LuaRocks is installed; 2) CC environment variable is unset; 3) uninstall luafilesystem module if it is installed.

Once the conditions outlined above are met, run the following command in a CLANG64 shell:

luarocks install luafilesystem

Note

The same behavior should be observed for other Lua modules like luasocket and lua-cjson.

Expected behavior

The Lua module should install normally.

Actual behavior

The building of C code fails.

Verification

• I have verified that my MSYS2 is up-to-date before submitting the report (see https://www.msys2.org/docs/updating/)

Windows Version

MSYS_NT-10.0-26100

MINGW environments affected

• MINGW64
• MINGW32
• UCRT64
• CLANG64
• CLANGARM64

Are you willing to submit a PR?

Yes, I have a PR prepared to fix this issue.