ghdl's ghw loader now integrated with gtkwave

http://home.nc.rr.com/gtkwave/

....I had to do a fair amount of patching to get the ghw.c patch to play
nice with the viewer, but it appears to work now. As it's part of the
source distribution, applying the patch is no longer required. The
win32 version can also be found on that webpage.

Report any bugs to the email address on the webpage, not here. I don't
use ghdl at all so I'd also need to be pointed to a ghw file that
causes specific problems to occur.

-t