I have a cross platform C++ project that targets and successfully compiles on Linux, OSX and Windows. I'm using GNU Make to handle the building on all platforms, gcc for compiling under Linux & OSX and cl.exe to compile under Cygwin on windows. My current workflow consists of coding under OSX and then building on each individual platform to test code portability. This process is somewhat time consuming and I was wondering if it is possible to automatically build on all platforms in one step?