Remove fatal error about host compiler if --use-local-env, --allow-unsupported-compiler and --ccbin are passed

I am a bit annoyed by nvcc host compiler detection logic. So if all three options --use-local-env, --allow-unsupported-compiler and --ccbin are passed to nvcc please simply assume that the users knows what is going on or only print a warning.

So I would like to use another clang-cl then installed with MSVC however if I try to do that I am either greeted with:

(a) nvcc fatal : Compiler 'clang-cl.exe' in PATH different than the one specified with -ccbin


(b) nvcc fatal : Host compiler targets unsupported OS.

It is a bit ridiculous to be greeted with (a) when using:

nvcc -allow-unsupported-compiler -ccbin clang-cl.exe -v --use-local-env

Since that is basically impossible (due to --use-local-env) and nvcc is seemingly using a different environment then specified. Secondly, explicitly passing the full path e.g. C:\Program Files\LLVM\bin\clang-cl.exe yields (b) although the target could be inferred from --use-local-env having vcvars being setup beforehand.

Please either provide a flag to ignore these warnings or fix the detection logic to consider these cases.

From my testing nvcc is looking for the vcvars.bat within Auxiliary folder although is --use-local-env used. From further testing it seems to search parent folders for the /VC/ folder and then looks into Auxiliary.