4.5-> 5.2 upgrade path issues

Hi All,
	Found an old box running FreeBSD 4.5 quite happily on our network.
Due to security issues (now I know the box exists), I've asked the admin
to update to 4.9 or Freebsd 5.2. He tried upgrading to FreeBSD 5.2 however
the build world failed with:

===> rescue/rescue/common
"/usr/src/share/mk/bsd.lib.mk", line 18: Malformed conditional
(defined(SHLIB_NA
ME) && ${SHLIB_NAME:M*.so.*})
"/usr/src/share/mk/bsd.lib.mk", line 18: Missing dependency operator
"/usr/src/share/mk/bsd.lib.mk", line 22: if-less endif
"/usr/src/share/mk/bsd.lib.mk", line 22: Need an operator
make: fatal errors encountered -- cannot continue
*PDATING r code 1

Updating has nothing about a proper procedure to get around this, so
what's the recommended upgrade path?

The box is running:

FreeBSD corvus.clearchain.com 4.5-RELEASE FreeBSD 4.5-RELEASE #0: Mon Jan
28 14:
31:56 GMT 2002
murray_at_builder.freebsdmall.com:/usr/src/sys/compile/GENERIC
i386

And we cvsuped to RELENG_5_2

Cheers,
	Benjamin