[CMake] Adding files to a project without building them

[Benjamin Schindler]

Hi

I have a project which has a multitude of different files:
cu, xsd, cpp, h
I built a rather complex build system to cope with all of them, but for 
Visual Studio users, this is not yet good enough: The files which are 
not included in an add_executable are not visible in the Visual Studio 
solution/project which is quite a pain. For header files this is no 
problem because I can just add them to the executable/library, but for 
xsd and other files, this is a problem as Visual Studio actually invokes 
some tools on the files which it should not.

I then tried to add the files using source_group() - and this did not 
work: Only files which are listed as sources in ADD_EXECUTABLE or 
ADD_LIBRARY are added to the source group, the others aren't.

How can I avoid this problem?

Thanks
Benjamin Schindler