How to add in a CMake project a global file extension (*.pde) to GCC which is treated like C++ code

Question

I have a very simple CMake script. Unfortunately, the project uses a *.pde file which is plain C++ or C code.

CMake is working with any file ending, but I get a comp

Answer 1

CMake doesn't do this for you:

http://public.kitware.com/Bug/view.php?id=14516