Windows/CMake: add /MP for multi process MSBuild

[th1000s]

Description

"The /MP option can reduce the total time to compile the source files on the command line. The /MP option causes the compiler to create one or more copies of itself, each in a separate process."

https://learn.microsoft.com/en-us/cpp/build/reference/mp-build-with-multiple-processes?view=msvc-170

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Yes, a compile option which modifies the build process...

Pull Request Type

• GitHub Workflow changes
• Documentation or Wiki changes
• Build and Dependency changes
• Runtime changes

Checklist

• I have tested my changes locally and verified that they work as intended.
• I have documented any new or modified functionality.
• I have reviewed the changes to ensure they do not introduce any unnecessary complexity or duplicate code.
• I understand that by submitting this pull request, I am agreeing to license my contributions under the project's license.

[bryanperris]

CI build time for windows took 58 seconds rather than 1 and a half minutes.

[th1000s]

Indeed, so:

• I have tested my changes locally in the cloud and verified that they work as intended.

Is an option to disable this parallelism needed? Not sure if -D CMAKE_CXX_FLAGS="/MP 1" works (no Windows here, this is copied from $WORK). I often use ninja -j1 so the output is cleaner, but that doesn't require a full cmake reconfigure.

[bryanperris]

Indeed, so:

• I have tested my changes locally in the cloud and verified that they work as intended.

Is an option to disable this parallelism needed? Not sure if -D CMAKE_CXX_FLAGS="/MP 1" works (no Windows here, this is copied from $WORK). I often use ninja -j1 so the output is cleaner, but that doesn't require a full cmake reconfigure.

Lets wait for a Windows based developer to check over this.

[bryanperris]

SaladBadger has approved the change