FreeBSD 5.2-RELEASE and blender

When using either the precompiled package (pkg_add -r) or
the locally compiled port of blender-2.25 I get the following
message:

/usr/libexec/ld-elf.so.1: /usr/lib/libc_r.so.5: Undefined symbol "__thr_jtable"

Googling for info I find that this was not uncommon with
-CURRENT about a year ago and it seems to be related to
FreeBSD 4.x compatibility.  I've got 4.x binary compatibility
installed as well as option COMPAT_FREEBSD4 in the
kernel config.

Am I missing something here?

Sean