avoid a hidden dependency on libiconv.so if it's installed in ${LOCALBASE}.
It's also possible now to build gimp without accidentally pulling in older
gimp headers from an installed gimp package. Also allow
gnome-libs/buildlink.mk to pull in much of the dependencies.
* Remove patch to pass $(INTLDEPS) to the compiler in modules/Makefile as
the gettext headers are found in ${BUILDLINK_DIR}/include which is already
passed through in CFLAGS.
* Remove GNOME_CONFIG=no from CONFIGURE_ENV. This was a leftover from when
there was a separate gimp-helpbrowser package that depended on gnome-libs
while the main gimp package only needed GTK+ and graphics libs. Since
there is only one consolidated gimp package now, we need the gnome-libs
dependency (more specifically, libgtkxhtml.so) to be correctly found for
the helpbrowser plugin to be built.
* Add settings for MPEG, LIBMPEG, and GAP_DECODE_MPEG to properly support
the MPEG library from graphics/mpeg-lib that changed it's name.
* Change -Wl,-E (conditionalized on ELF) to -Wl,--export-dynamic which works
across both the ELF and a.out linkers.