[llvm] [LLVM][CMake] Set LANG to "C" before linker detection. (PR #95913)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

How about
```
execute_process( 
    COMMAND ${CMAKE_COMMAND} -E env LANG=C ${command}
    ...
)
```
would that solve the issue?


https://github.com/llvm/llvm-project/pull/95913