[Dune] CMake: how to set different builddir

[Agnese, Marco]

Hi,
a very quick and stupid question about CMake. I took a look at the CMake FAQ but I didn't find anything.

I compile the core modules in ~/build-core and I want to compile dune-foo, which depends on the core modules, in ~/build-foo. 

If I call dunecontrol --buildir=~/build-foo it fails with the following error

ERROR: could not find /dune.module

which, I suppose, means that it can't find the core modules since are built in a different folder.

How can I fix the issue?  Do I have to set some environment variable to add the built core modules to the CMake path. Or do I have to do something else?

Thank you for your help,
cheers,
Marco.