X11/Intrinsic.h not found, ALT_X11_PATH=/opt/X11

[Alan Bateman]

I upgraded a Mac to 10.8.2 and Xcode 4.5.2 over the break, now I'm 
trying to get the jdk7u/jdk7u-dev, jdk8/tl and jigsaw/jigsaw forests 
building again. I installed XQuartz 2.7.2 so I have X11 and jdk8/tl 
builds fine with the new build (except for the "images" target, there's 
an issue with sed there).

For the old build (jdk7u-dev and jigsaw) then AWT won't build because it 
can't find X11/Intrinsic.h. With XQuartz then it looks like the X11 bits 
are in /opt/X11. The include files are there so I tried to build with 
ALT_X11_PATH=/opt/X11 but that doesn't help. Is there anything else I 
need to know?

-Alan