GCC debug flags cleanup

Hi,

I've created a patch that cleans up FreeBSD Makefiles that unconditionally set the -g flag for GCC. The motivation for this is that it should be possible to add or remove this flag globally via e.g. CFLAGS (it's part of my quest to produce deterministic builds).

I'm not very familiar with GCC or the build infrastructure, so I'd be grateful if someone would review it and possibly commit.

http://dev.affect-it.dk/gcc_debug_flags.diff

Thanks,
Erik