MSVC installation issues

[aminya]

This is now mostly fixed for VS2019 and VS2017. But still requires some more testing. The best way to fix it is to run the tests and debug the issues.

Old Description

Copied from https://github.com/jberezanski/ChocolateyPackages/issues/117

I am using visualstudio2017buildtools and visualstudio2019buildtools to set up MSVC. However, my tests fail because vcvars.bat cannot find the toolset.

https://github.com/aminya/setup-cpp

    invalid parameters
    [ERROR:vcvars.bat] Toolset directory for version '15.9' was not found.
    [ERROR:VsDevCmd.bat] *** VsDevCmd.bat encountered errors. Environment may be incomplete and/or incorrect. ***
    [ERROR:VsDevCmd.bat] In an uninitialized command prompt, please 'set VSCMD_DEBUG=[value]' and then re-run
    [ERROR:VsDevCmd.bat] vsdevcmd.bat [args] for additional details.
    [ERROR:VsDevCmd.bat] Where [value] is:
    [ERROR:VsDevCmd.bat]    1 : basic debug logging
    [ERROR:VsDevCmd.bat]    2 : detailed debug logging
    [ERROR:VsDevCmd.bat]    3 : trace level logging. Redirection of output to a file when using this level is recommended.
    [ERROR:VsDevCmd.bat] Example: set VSCMD_DEBUG=3
    [ERROR:VsDevCmd.bat]          vsdevcmd.bat > vsdevcmd.trace.txt 2>&1

https://github.com/aminya/setup-cpp/runs/3618796745?check_suite_focus=true#step:7:302

[aminya]

Found a use-case https://github.com/rollbear/trompeloeil/issues/265