While I was trying to compile an rrdtool extension, I found what seem to be bugs in several other extensions.
There seem to be incorrect references to other lib .la file locations. All the bugs just involve files that are referenced in /usr/lib but are actually located in /usr/local/lib or vice versa.
pango-dev.tcz has two files with problems:
/usr/local/lib/libpango-1.0.la
/usr/local/lib/libpangocairo-1.0.la
In libpango-1.0.la, there is an incorrect reference to /usr/local/lib/libffi.la, instead of the correct location /usr/lib/libffi.la.
In libpangocairo-1.0.la, there is an incorrect reference to /usr/lib/libXau.la (and libXdmcp.la), instead of the correct locations /usr/local/lib/libXau.la (and libXdmcp).
cairo-dev.tcz has three files in /usr/local/lib/libcairo*.la with the libXau/libXdmcp location errors.
In libxcb-dev there are 25 .la files with the libXau/libXdmcp location error.
In Xorg-7.7-dev there are 28 .la files with the libXau/libXdmcp location error.
I don't know if the libXau/libXdmcp files (from Xorg-7.7-dev) are in the wrong location or if these tcz files just reference the wrong location.
Changing all the references to where the files are actually located seems to allow my compile to complete successfully.
I don't know if anyone else has run into this. But FYI.