[CMake] Nice handling of code coverage option?

[Brad Hards]

Hi,

I've seen a few projects that do code coverage setup within cmake, but nothing 
that does it really "nicely". 

My idea of nice is that the coverage:
- it mostly done in a module that I can just "INCLUDE( MagicCoverage )"
- is controlled by a cmake OPTION()
- automatically gets the right coverage tool for the CMAKE_CXX_COMPILER (or 
warns about not being able to find an appropriate coverage tool)
- adds the right compiler / linker flags
- has a makefile (or equivalent) target to run the coverage tool.

It would be nice if it also handled the C compiler and warned if there was a 
conflict. 
lcov support would also be nice.

It would be enough for now to just handle g++ / gcov, although I'd like to be 
able to extend to at least the Intel compiler.

Does anyone have such a thing (or a similar thing) that they can share?

If not, does anyone have parts that might help (especially reliably detecting 
which compiler is being used)?

Thanks for any suggestions.

Brad