On Mar 9, 2011, at 7:00 AM, Jeremy wrote:

My guess is that they are doing some '#include <png.h>' without the CPPFLAGS given to them by pkg-config, so they're getting /opt/X11/include/png.h rather than /opt/X11/include/libpng14/png.h ... but I can't really tell for certain because you've never provided any logs showing the problem.

Since libpng in 2.6.1_rc1 is the same as 2.6.1_beta, I am pretty sure the problem was a config issue on my end that I missed, probably a stray file I neglected to delete. Your answer was helpful, and I didn't want to waste bandwidth debugging my config. FYI the app aggressively looked for libpng14.pc, then libpng12.pc, then libpng.pc. It ignored what version was intended to be used from sym links. It looked in every possible location for libpng14.pc first, ignoring the preferred location that appears first in PATH., LD_LIBS, etc. The app actually compiled fine until libpng15 came along. The hurdles I had to go through shouldn't have happened, and were not due to anything faulty in XQuartz. I have fed this back to the app developers. I have a much more important and difficult problem with this app that is less clear where the problem lies, and I would rather spend our cycles looking at that. I will make a separate post to keep topics organized. I will post detailed logs for that, since I'm sure it isn't a user config issue.