CMake: Align MSVC runtime (MD[d], MT) options to engine

[enetheru]

SCons does not link to /MDd or /MTd
If needed in the future a flag can be introduced like the engine code at platforms/windows/detect.py:459

This solves issue #1459

[AThousandShips]

Please rename your PR to describe what your fix does

[enetheru]

Please rename your PR to describe what your fix does

sorry about that.

[dsnopek]

Thanks!

Per this comment from bruvzg, I think this is what we should do.

@enetheru Could you also amend the first line of the commit message to match the PR title? We prefer descriptive messages (versus issue number references) there too

[enetheru]

OK so here's the plan I am proposing:

Godot engine uses a flag debug_crt to specify linking to the debug runtime library for MD only, not MT.
link to source

 if env["debug_crt"]:
        # Always use dynamic runtime, static debug CRT breaks thread_local.
        env.AppendUnique(CCFLAGS=["/MDd"])
    else:
        if env["use_static_cpp"]:
            env.AppendUnique(CCFLAGS=["/MT"])
        else:
            env.AppendUnique(CCFLAGS=["/MD"])

godot-cpp doesn't have this option and only differentiates on static_cpp
link to source

        if env["use_static_cpp"]:
            env.Append(CCFLAGS=["/MT"])
        else:
            env.Append(CCFLAGS=["/MD"])

I ammend this PR so that both CMake and SCons reflect the options the engine has.

[dsnopek]

Matching Godot's build options sounds good to me!

[enetheru]

I didnt realise renaming my branch will close this PR.

[dsnopek]

Thanks! Looks good to me :-)