Public release 0.54 is Motif based, and while it is known to compile
with Hungry Product's
lesstif
.
I've never had much luck with it. Menus don't work correctly and
performance is sluggish on my system.
Developer's release 0.61 compiles pretty well (there are no binary versions available that I'm aware of) except for the JPEG, TIFF, AND PGN format plug-ins. I've found that the 0.54 versions of these plug-ins work well under 0.61, but few, if any other plug-ins compiled under 0.54 will work under 0.61. 0.61 is entirely gtk based and no longer has any need of Motif or Lesstif, more or less.
The December Gimp, from what I've read in the developer's newsgroup, is very difficult to compile and is at present, almost non-functional, so I've never bothered with it. 0.61 is buggy enough for me.