gimp-jp2 needs to be aware whether it was compiled against gtk2 +x11 or +quartz

[neverpanic (Clemens Lang)]

Hi,

when installing the pre-built gimp-jp2 package from packages.macports.org, rev-upgrade complains, because it links against some X libraries not present on my system due to my gtk2 being -x11+quartz:

--->  Scanning binaries for linking errors
Could not open /opt/local/lib/libXfixes.3.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libXdamage.1.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libXcomposite.1.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libXcursor.1.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libXi.6.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libXinerama.1.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libgdk-x11-2.0.0.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

Could not open /opt/local/lib/libgtk-x11-2.0.0.dylib: Error opening or reading file (referenced from /opt/local/lib/gimp/2.0/plug-ins/jp2)
DEBUG: Marking /opt/local/lib/gimp/2.0/plug-ins/jp2 as broken

--->  Found 8 broken file(s), matching files to ports
--->  Found 1 broken port(s), determining rebuild order
DEBUG: Broken: gimp-jp2
DEBUG: Processing port gimp-jp2 @0:2.2.0_6
DEBUG: Processing port gimp @0:2.8.4_0
--->  Rebuilding in order
     gimp-jp2 @2.2.0

Thus, gimp-jp2 needs to have variants for x11 and quartz, it should use the active_variants portgroup to ensure proper variant dependencies and it should probably also change its default variant depending on what the user has installed already.

See #37931 and r102556 for a similar case of a different port.