Hi,
I can't figure out where the headers have changed between gsdl 2.39
and gsdl 2.40, but I get this as well. The solution is to edit
the file gsdl/src/gsdl/packages/mg/sysfuncs.h and at about line 283
or so, remove the line that says
#include <getopt.h>
The problem is that mg was written quite a while ago and does a lot
of portability stuff itself, but since it was written a lot of the
stuff it does is now in all the main c libraries anyway, so its own
stuff is conflicting with system libraries and headers.

That was the only change I needed to compile on os x 10.2.4.

Anyway, after finding out from the other developers what's in
gsdl 2.40 that isn't in gsdl 2.39, I'll see about updating the Mac
binary in the next few days.

John McPherson