undefined X symbol ?

Hello,

I'm running Obsd 3.3/68k and am trying if an application is portable to
it.
I am referring to Nebula IRC, a light-weight IRC client
(Http://nebula-irc.sf.net) that I develop myself.  The app uses
configure from autotools.
I was able to compile and run nebula on really many platforms, but not
here: the application configures and compiles, but fails to launch:

frodo:nebula-0.3 {104} ./nebula
/usr/libexec/ld.so: Undefined symbol "_XShapeQueryExtension" called from
nebula:/usr/local/lib/libXm.so.2.1 at 0x4180d7c


the motif packages comes from ports:
openmotif-2.1.30.5 Motif toolkit
Any ideas?


Thanks,
  Riccardo