Xcode: xcodebuild -jobs always requires argument when doing parallel build
the xcodebuild tool seems to require an argument for parallel jobs:
16:34 $ xcodebuild -jobs
xcodebuild: error: option '-jobs' requires an argument
So for the code at: https://gitlab.kitware.com/cmake/cmake/blob/v3.12.1/Source/cmGlobalXCodeGenerator.cxx#L362 it seems like we need to always pass a value. In the case where no value has been passed via CLI nor ENV var, maybe do something similar to the detection of ProcessorCount?