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 compil
If I understand the OP correctly, the question isn't about replacing make but how to launch the build on each platform?
I'd suggest using http://jenkins-ci.org/ - it's java and can be run on Windows, Linux, OSX, etc. It can be configured to launch build jobs concurrently so that any time you want to do a build each platform could be launched simultaneously.
The learning curve for jenkins isn't terrible but it probably will take about 3-4 hours to get working right, once you do however it's smooth sailing.
If you want to be pro, you can have it poll your source repo and it'll launch builds automatically after commits.