[CMake] copying the contents of a directory with cpack

[Niall Dalton]

Hi,

I have a custom target that creates doxygen documentation from my C  
header files. I'd like, as part of my cpack configuration in my main  
CMakeLists.txt, to copy the directory containing the doxygen output  
into the .tar.gz package.

What is the simplest way to do this?

thanks!
niall