Low-level build functions
Launch make from a build dir. Launch make -j <num_jobs> in num_jobs is not none
Launch nmake from a build dir. For this to work, you may need to be in a Visual Studio command prompt, or having run vcvarsall.bar
Launch msbuild with correct configuration (debug or release), and with correct switch if num_jobs is not None
Convert a number of jobs to a list of cmake args