Reset PROCESSOR_ARCHITECTURE on start

[BillyONeal]

A customer reported a problem where sometimes vcpkg-cmake can't detect that Ninja is safe to use. There, despite being on an amd64 system, this block didn't detect that things were OK:

https://github.com/microsoft/vcpkg/blob/08c4e71048eb54733d9b180a28b9b1d7ce637454/ports/vcpkg-cmake/vcpkg_cmake_configure.cmake#L55-L61

We are unable to replicate the problem, but suspect that they may be in an environment where PROCESSOR_ARCHITECTURE isn't set properly, similar to what we experienced in #769 .

Try to fix this problem by explicitly setting it to what it should be.

Before:

PS D:\vcpkg> rm env:PROCESSOR_ARCHITECTURE
Remove-Item: Cannot find path 'Env:\PROCESSOR_ARCHITECTURE' because it does not exist.
PS D:\vcpkg> rm env:PROCESSOR_ARCHITEW6432
Remove-Item: Cannot find path 'Env:\PROCESSOR_ARCHITEW6432' because it does not exist.
PS D:\vcpkg> echo "PROCESSOR_ARCHITEW6432: $env:PROCESSOR_ARCHITEW6432 PROCESSOR_ARCHITECTURE: $env:PROCESSOR_ARCHITECTURE"
PROCESSOR_ARCHITEW6432:  PROCESSOR_ARCHITECTURE:
PS D:\vcpkg> .\vcpkg.exe env
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%

D:\vcpkg>exit
PS D:\vcpkg> echo "PROCESSOR_ARCHITEW6432: $env:PROCESSOR_ARCHITEW6432 PROCESSOR_ARCHITECTURE: $env:PROCESSOR_ARCHITECTURE"
PROCESSOR_ARCHITEW6432:  PROCESSOR_ARCHITECTURE:
PS D:\vcpkg> .\vcpkg.exe env C:\Windows\SysWOW64\cmd.exe
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%

After:

PS D:\vcpkg> rm env:PROCESSOR_ARCHITECTURE
PS D:\vcpkg> rm env:PROCESSOR_ARCHITEW6432
Remove-Item: Cannot find path 'Env:\PROCESSOR_ARCHITEW6432' because it does not exist.
PS D:\vcpkg> echo "PROCESSOR_ARCHITEW6432: $env:PROCESSOR_ARCHITEW6432 PROCESSOR_ARCHITECTURE: $env:PROCESSOR_ARCHITECTURE"
PROCESSOR_ARCHITEW6432:  PROCESSOR_ARCHITECTURE:
PS D:\vcpkg> .\vcpkg.exe env
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: AMD64

D:\vcpkg>exit
PS D:\vcpkg> echo "PROCESSOR_ARCHITEW6432: $env:PROCESSOR_ARCHITEW6432 PROCESSOR_ARCHITECTURE: $env:PROCESSOR_ARCHITECTURE"
PROCESSOR_ARCHITEW6432:  PROCESSOR_ARCHITECTURE:
PS D:\vcpkg> .\vcpkg.exe env C:\Windows\SysWOW64\cmd.exe
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: AMD64 PROCESSOR_ARCHITECTURE: x86

[BillyONeal]

I can't replicate the user's exact thing but I do see after rm env:PROCESSOR_ARCHITECTURE:

.\vcpkg.exe install libxml2:x64-windows --binarysource=clear
[...]
Building libiconv:x64-windows...
[...]
CMake Error at scripts/cmake/vcpkg_configure_make.cmake:19 (message):
  Unsupported host architecture in z_vcpkg_determine_autotools_host_cpu!

which after this change becomes:

.\vcpkg.exe install libxml2:x64-windows --binarysource=clear
[...]
Building libiconv:[email protected]#1...
[...]
Elapsed time to handle libiconv:x64-windows: 5.2 min

[BillyONeal]

Interestingly this is also fixed if the values are set to bogus. I don't know how but I'm just going to be happy it is:

PS D:\vcpkg> echo "PROCESSOR_ARCHITEW6432: $env:PROCESSOR_ARCHITEW6432 PROCESSOR_ARCHITECTURE: $env:PROCESSOR_ARCHITECTURE"
PROCESSOR_ARCHITEW6432: fish PROCESSOR_ARCHITECTURE: fish
PS D:\vcpkg> .\vcpkg.exe env C:\Windows\SysWOW64\cmd.exe
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: AMD64 PROCESSOR_ARCHITECTURE: x86

D:\vcpkg>exit
PS D:\vcpkg> .\vcpkg.exe env
Microsoft Windows [Version 10.0.22631.2715]
(c) Microsoft Corporation. All rights reserved.

D:\vcpkg>echo PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: %PROCESSOR_ARCHITECTURE%
PROCESSOR_ARCHITEW6432: %PROCESSOR_ARCHITEW6432% PROCESSOR_ARCHITECTURE: AMD64

D:\vcpkg>exit