GRASS GIS on Mac OS X

GEOS version: 2.1.3
refractions.net

In a Terminal type:

$ cd path_to_folder_containing_geos_source.tar.bz2
$ tar -jxf geos-2.1.3.tar.bz2
$ cd geos-2.1.3
$ ./configure --mandir=/usr/local/share/man
$ make
$ sudo make install-strip

Make sure to do the make install-strip, instead of the usual make install, or you will get a HUGE library. It's just debugging stuff.