> I think I got it.  The problem appears when ABI=64 is in mk.conf.  When
> this happens, LIBABISUFFIX is automatically set to 64, and it seems that
> buildlink will only allow -L directories that end in that string.
> Therefore, it correctly uses /usr/lib64 but traps ${PREFIX}/lib, as it
> doesn't have the 64 suffix.
> 
> If this is the reason... I don't know how to fix it.

one quick and dirty fix might be to set LIBABISUFFIX= in mk.conf (did that
on my IRIX 5.3 system where the ABI stuff is partially meaningless anyway).
Then of course the /usr/lib64 stuff is no longer added.

mk/bsd.pkg.mk has

CONFIGURE_ARGS+=        --x-libraries=${X11BASE}/lib${LIBABISUFFIX}

mk/bsd.pkg.use.mk has

.if defined(USE_X11)
X11_LDFLAGS+=           ${COMPILER_RPATH_FLAG}${X11BASE}/lib${LIBABISUFFIX}
X11_LDFLAGS+=           -L${X11BASE}/lib${LIBABISUFFIX}
.endif

Here one could add the same thing without ${LIBABISUFFIX} (and if one did
it very nicely the above would only be added if ${LIBABISUFFIX} was nonempty)

I do not see at first glance though where X11_LDFLAGS is actually being
used later on.

Georg

-- 
Georg Schwarz    http://home.pages.de/~schwarz/
 georg.schwarz@freenet.de  +49 178 8545053