This info is outdated - follow the instructions at http://piksel.org/frei0r
The current version of MøB operates with this header. The header itself is included in the MøB source (modules/effects/frei0r/frei0r.h). In order to use the effects (the two offered by the Gephex crew plus my simple flippo one, that you are encouraged to distribute, FWIW) you should untar the plugins directory of the frei0r tar file
(http://frei0r.kexbox.org/frei0r-2004-11-11.tar.bz2)
into a directory of your choice, and put a link of modules/effects/frei0r/frei0r.h in its parent directory. For example:
cd mkdir frei0r cd frei0r tar xvfj frei0r-2004-11-11.tar.bz2 frei0r-2004-11-11/plugins mv frei0r-2004-11-11/plugins . rmdir frei0r-2004-11-11 ln -s modules/effects/frei0r/frei0r.h . cd plugins/distort0r make cd ../invert0r make cd ../.. ln -s `find plugins -name '*.so'` .
At this point you should have the two .so files in /frei0r
export FREI0R_PATH=/frei0r/
should allow you to see the frei0r effects in the list of MøB's available effects.