[Dune] [CMake] Set external ALUGrid

[Robert Kloefkorn]

Hello Christoph,

> if you advise everybody to not use CMake, it will never improve. We
> decided to make the switch to get more feedback. As I wrote, it worked
> for me and I was more then willing to investigate the issue.

are you suggesting that we should not trust you anymore?
And, I definitely don't agree with the workflow of submitting some stuff
and the let others sort out the flaws that come with it.

If you want to use dune-alugrid then it is indeed a good idea to not use
the cmake build system since it does not support all features yet (zlib,
zoltan, sionlib, etc). I have spent nearly a full week in November
getting the dune-alugrid and dune-fem cmake support to run with the
feature set that the current autotools build system has. It was tedious
to say the least and of course cmake is not the great salvation as some
of the developers seem to believe. I don't think that we have gained
anything from the switch to cmake besides destabilizing the whole
project (Where are the millions of Windows users that might benefit from
that?).

In general I don't think that it is a good idea and good practice to
make every user a beta tester. That's just bad style, IMHO.

Best,

Robert