Enable Windows Emscripten build

[mcbarton]

Description

Please include a summary of changes, motivation and context for this PR.

This PR enable xeus-cpp to be cross compiled to Emscripten on a Windows platform (following Emscripten build instructions in CppInterOp). The 2 changes are as follows

1. Add .bat suffix to embuilder if on Windows (otherwise it uses the one made for Unix systems and errors)
2. Change \ to / in ESCAPED_XEUS_CPP_RESOURCE_DIR and ESCAPED_SYSROOT_PATH (\ gets removed from the preloaded path otherwise)

To see these changing allow an Emscripten build of xeus-cpp to work and pass all Emscripten tests, see this PR in CppInterOp compiler-research/CppInterOp#647

Fixes # (issue)

Type of change

Please tick all options which are relevant.

• Bug fix
• New feature
• Added/removed dependencies
• Required documentation updates

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 81.78%. Comparing base (23e11aa) to head (8e910d3).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #362   +/-   ##
=======================================
  Coverage   81.78%   81.78%           
=======================================
  Files          20       20           
  Lines         950      950           
  Branches       87       87           
=======================================
  Hits          777      777           
  Misses        173      173           

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[vgvassilev]

Do we want to work in the windows ci here, too?

[mcbarton]

Do we want to work in the windows ci here, too?

@vgvassilev xeus-cpp uses Emscripten forges emsdk, which is only available for very particular platforms. When we asked previously for them to make emsdk available on Windows before the request was rejected. I could add a Windows Emscripten build here too, but we would need to get the upstream emsdk to achieve this. What would you like me to do?

[vgvassilev]

Do we want to work in the windows ci here, too?

@vgvassilev xeus-cpp uses Emscripten forges emsdk, which is only available for very particular platforms. When we asked previously for them to make emsdk available on Windows before the request was rejected. I could add a Windows Emscripten build here too, but we would need to get the upstream emsdk to achieve this. What would you like me to do?

I am not sure what's our path forward. We can merge that PR as it is if it helps with anything. However, it'd probably regress without any way of testing even small parts of this code for that platform..

[mcbarton]

Do we want to work in the windows ci here, too?

@vgvassilev xeus-cpp uses Emscripten forges emsdk, which is only available for very particular platforms. When we asked previously for them to make emsdk available on Windows before the request was rejected. I could add a Windows Emscripten build here too, but we would need to get the upstream emsdk to achieve this. What would you like me to do?

I am not sure what's our path forward. We can merge that PR as it is if it helps with anything. However, it'd probably regress without any way of testing even small parts of this code for that platform..

@vgvassilev This platform would be tested from CppInterOp initially through the ci in this PR compiler-research/CppInterOp#647 . Once this PR is in I will add browser tests. I think its ok to work under the principle that if this workflow fails, then we implement a basic workflow in xeus-cpp to debug. Will that suffice? Without this PR going in, that PR in CppInterOp is dead in the water without any way to move forward.

To be fair xeus-cpp already doesn't test on platforms that CppInterOp does for the Emscripten xeus-cpp, e.g. osx x86 and Ubuntu arm.

[vgvassilev]

LGTM!