In my system, I have dev-lang/swig-1.3.40-r1, which compiles fine.
also dev-lang/swig-2.* does.
swig-1.3.29 was relesed on sourceforge on 2006-03-21.
so, I think, ros should update his own swig depedency.

how may I skip swig compilation and use my local version of swig instead?

You can't unfortunately. We only use swig to create wxPython bindings for certain controls, and it requires a specific and patched version of swig. This problem will go away when we move to Qt.

Josh