Today I released a little, but helpful tool on github. It is called Single-C-File and basically merges whole C/C++ Projects into one .cxx file.
I think this is quit usefull when working with c/c++ libraries, merging them makes it very easy to add them to a project, but they still are full cross platform complatilbe and you still can change the code if you want.
Single-C-File on github:
Adrian Dawid 