[CMake] Parallel builds

[Greg Marr]

From: J Decker [mailto:d3ck0r at gmail.com] 
Sent: Wednesday, September 16, 2015 1:30 PM
To: Greg Marr
Cc: Petr Bena; Cory Quammen; cmake at cmake.org; Bill Hoffman
Subject: Re: [CMake] Parallel builds

	/mp has no effect on cmake projects since each file is compiled with a
	separate command... it relies more on msbuild /m:<num> option...

	from https://msdn.microsoft.com/en-us/library/bb385193.aspx?f=255&MSPPError=-2147217396

	cl /MP7 a.cpp b.cpp c.cpp d.cpp e.cpp

	but cl is invoked for each source already; multiple sources aren't passed to cl.

That's not true for the Visual Studio generator.  CMake generates project files, and Visual Studio builds them just like any other project file, including using the /MP flag.