GTK/GDK on OSX

[H William Wellliver III]

I’m running into some build problems on OSX. It seems that the GTK 
module assumes that if a system is NT that gdkwin.h is used and 
otherwise gdkx.h is used. Unfortunately, it seems that on some builds of 
GTK/GDK for OS X, neither of those is correct and that gdkquartz.h 
should be used. I’m guessing that some configure tests are needed to 
determine which of the 3 files is actually present. However a quick look 
at configure.in leaves me unsure how best to include that. Anyone with 
more expertise in the GTK module’s inner workings care to weigh in?

Bill