rake clean doesn't clean everything

[andystanton]

The glfw library generates a configuration header based on the OS that cmake was invoked from. This header file is not deleted, so in the event the cmake'd sources are copied to another OS, some settings specific to the previous OS may be maintained despite the rake clean task.

Either the above process is bad or git clean should be invoked to clean each source root as follows:

git clean -dff
git clean -dffX

The first cleans everything except the contents of .gitignore. The second cleans only the contents of .gitignore.