Luau compilation fails with the wasm32-unknown-emscripten target on Windows. #2
Description
When compiling mlua with the luau feature using cargo build -target wasm32-unknown-emscripten on a Windows machine, an error occurs where the compiler believes that /std:c++17 is a path to a compiled file:
warning: mlua-sys@0.6.0: em++: error: /std:c++17: No such file or directory ("/std:c++17" was expected to be an input file, based on the commandline arguments provided)
error: failed to run custom build command for `mlua-sys v0.6.0`
[...]
error occurred: Command "cmd" "/c" "em++.bat" "-O2" "-ffunction-sections" "-fdata-sections" "-fPIC" "--target=wasm32-unknown-emscripten" "-I" "C:\\Users\\jeuxj\\.cargo\\registry\\src\\index.crates.io-6f17d22bba15001f\\luau0-src-0.9.1+luau625\\luau\\Ast\\include" "-I" "C:\\Users\\jeuxj\\.cargo\\registry\\src\\index.crates.io-6f17d22bba15001f\\luau0-src-0.9.1+luau625\\luau\\Common\\include" "-std=c++17" "/std:c++17" "-fexceptions" "-fno-math-errno" "-DLUAI_MAXCSTACK=1000000" "-DLUA_VECTOR_SIZE=3" "-DNDEBUG" "-o" "C:\\Users\\jeuxj\\FastDev\\Proj\\target\\wasm32-unknown-emscripten\\release\\build\\mlua-sys-7b31f19e5a5927e4\\out\\luau-build\\lib\\9bb9ba4c8bd32a76-Ast.o" "-c" "C:\\Users\\jeuxj\\.cargo\\registry\\src\\index.crates.io-6f17d22bba15001f\\luau0-src-0.9.1+luau625\\luau\\Ast\\src\\Ast.cpp" with args cmd did not execute successfully (status code exit code: 1).
This likely due to both -std=c++17 and /std:c++17 arguments being specified, which causes the compiler to be weirdly confused (see https://github.com/mlua-rs/luau-src-rs/blob/main/src/lib.rs#L116-L117)