[CMake] warn if features used that require >cmake-x.y

[Alexander Neundorf]

On Thursday, July 02, 2015 04:13:40 Stuermer, Michael  SP/HZA-ZSEP wrote:
> Have a look at cmake_minimum_required() and cmake_policy(). I think with
> these both it should be possible to verify you are using a cmake version
> that provides all features which are required by your project.

no, what he is talking about is the other way round.
He wants to make sure nobody accidentially introduces cmake code which 
requires a newer version of cmake than what cmake_minimum_required() states.

I think that's really hard to implement, but it would be nice to have.

Alex