It seems to fail on the linker step… but this didn’t used to matter.
I just used a raw command line myself to test it out.
D:/.../vc/14.28.29910/bin/Hostx64/x64/cl.exe D:\...\build\ninja\wnow64\CMakeFiles\3.21.0-rc2\CompilerIdCXX\CMakeCXXCompilerId.cpp -I__does_not_exist
Microsoft (R) C/C++ Optimizing Compiler Version 19.28.29910 for x64
Copyright (C) Microsoft Corporation. All rights reserved.
CMakeCXXCompilerId.cpp
Microsoft (R) Incremental Linker Version 14.28.29910.0
Copyright (C) Microsoft Corporation. All rights reserved.
/out:CMakeCXXCompilerId.exe
CMakeCXXCompilerId.obj
LINK : fatal error LNK1104: cannot open file 'LIBCMT.lib'