grass-6.2.1 and grass-6.2.3 don't compile with gcc-4.3.1: Errors in: /var/tmp/portage/sci-geosciences/grass-6.2.1/work/grass-6.2.1/raster/r.terraflow Debian have a patch: http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=12;filename=gcc43-1.dpatch;att=1;bug=461673 that works with grass-6.2.3 for me.
*** This bug has been marked as a duplicate of bug 217917 ***