Use clang-cl for Windows

[SuibianP]

I am trying to build the llnode module on Windows, which can only be built with clang-cl. The project previously (ab)used the passthrough of arguments to msbuild to configure the CLToolPath and CLToolExe properties, which has hence been fixed in #1164. (nodejs/llnode#321, nodejs/llnode#377)

I have attempted the following to no avail,

1. Add in binding.gyp

"msbuild_settings": {
    "ClCompile": {
        "CLToolPath": "<(cl_tool_path)",
        "CLToolExe": "<(cl_tool_exe)",
    },
},

This does put the properties into the vcxproj, but in the ClCompile section. https://stackoverflow.com/a/31362960/12385184

2. CC and CXX environment variables (https://github.com/nodejs/node-gyp/issues/2813#issuecomment-1462523117)

This does have some effect on the configure phase, but only accepts GCC (not CL) compatible compilers, and it has no effect on the building phase which still uses CL.exe.

---

This issue might be a case of #1537 if there is no special way to specify the compiler executable on Windows.

• Node Version: node v18.20.4 npm 10.7.0
• Platform: Microsoft Windows 11 Enterprise 10.0.22631 N/A Build 22631 x64-based PC
• Compiler: MSBuild version 17.11.2+c078802d4 for .NET Framework 17.11.2.32701 MSVC 19.41.34120 for x64
• Module: https://github.com/nodejs/llnode

[SuibianP]

Without changes to gyp and without breaking backward compatibility, the only way I can think of to pass arbitrary parameters is to prepend some character illegal in msbuild target names, such as ? or (. It is going to be rather ugly that way though... node-gyp build target1 target2 ?/p:CLToolExe="C:\bin\LLVM\clang-cl.exe" ?/p:CLToolPath="C:\bin\LLVM"

A reasonable compromise might be to pass through all arguments beginning with / to msbuild, on the assumption that target names rarely begins with a slash (although it is probably legal).

@cclauss any comments?

[cclauss]

Sorry, I am not a Windows user.