OK, I just uploaded 4 packages into ftp.gnustep.org/pub/incoming! The packages are gnustep-make, -base, -gui, and -back. I decided to split them up so that it could become more obvious what is being installed. The package gnustep-base requires libffi, which is actually included in the Slackware gcc package, so that shouldn't be a problem.
Don't put those packages up for distribution as of yet, please. I'd like to get some feedback first! There's already one thing I need to change, just for consistency (move xinitrc.gnustep from -gui to -back since gpbs is installed by -back and not -gui). Let me know what else needs work so I can fix it.
I haven't personally tested -gui or -back-art, so I need to be sure they work! I'll test them whenever I get around to building GWorkspace.
I'll also be making GORM, ProjectCenter and GWorkspace packages some time this week, I'll let you guys know whenever I have them up.