Don't add '-j' argument if parallelJobs <= 1

[mark-ulrich]

This change addresses item #1958

This changes behavior

The following changes are proposed:

• Respect the parallelJobs configuration to avoid parallel builds when it is configured to less than 2

The purpose of this change

Previously, the '-j' option would be passed to CMake even if the parellelJobs option was set to 1. This could cause issues with the build system. For example, passing the '-j' argument will cause CMake to actively remove the '/MP' flag in Visual C++, effectively disabling multi-processor compilation.

Other Notes/Information

Perhaps it would be best to add a configuration option to disable this automatic passing of '-j' altogether. However, this fix is sufficient when setting parellelJobs to 1.

[ghost]

All CLA requirements met.

[bobbrow]

So the intended behavior change in the setting is that you can now set the parallelJobs to 1 to disable our passing of -j to CMake? We should update package.nls.json to document this.