[AD] A patch to fix a bug in allero gui d_menu

I ran into a problem with d_menu_proc not filling up its whole area, a code example and a output screen shot can be seen at http://www.allegro.cc/forums/thread/591107/667363#target

I have created a patch following the instuructions on the wiki, I have tested the code on both windows and linux and it seemed 100%.

Its probably preferable to use the patch that is attached here not the allegro.cc one, as this was created by svn diff against 4.2, rather than local files. It is attached, or if attachments are striped it can be grabbed here http://www.timorg.net/gui.c.patch

I hope that this is all good and thank you for all the hard work you guys have done :)

-Timmy