Ah, now I'm remembering more about what the problems where.
1. Shared libraries and modules are the same on Linux (and lots of other Unices) but are
different on the Mac. Libtool had a difficult time understanding this.
2. Until fairly recently (Tiger, iirc) shared libraries couldn't be easily dlopened on the
mac, only modules could.
Since KDE makes extensive use of dlopen-ing modules to accomplish things this made things
quite tricky and libtool wasn't really that much help.
So, yeah, quite a different runtime system. Newer versions of OS X have gotten quite a bit
better on the dlopen-ing front, but they are still fundamentally different. And, I wouldn't
even try to use libtool to create OS X frameworks....