Solving some "Symbol not found" problems for libJPEG, libTIFF, libGL, libPng

[khyox]

I experienced this issue when I incorrectly set up
DYLD_LIBRARY_PATH to include /opt/local/lib.
So, as already advised by Daniel, don't do so.

Thanks to all the contributors to this post,
all of you helped me to discover the origin
of the trouble that I experienced suddenly
when I tried to 'upgrade outdated'.

PS out-of-topic: The "more than 80 character"
per fine filter of this web is really annoying...