. compile cleanly against 8.4 with -Wall on i386 and amd64;
. use OS' run-time linker instead of dlopen-ing libpng,
libjpeg, libtiff inside;
. stop using TIFF's _internal_ headers for anything.
This changes are quite radical, but seem to work with anything I have.
Vendor's own tests pass except for some differences in PNG images --
most likely due to changes in PNG library since 2002.
Stop requiring specific versions of jpeg, tiff, png -- we don't really care.
Bump up PORTREVISION.
4ba76fa965