FreeBSD-9.0-BETA3/amd64 (CLANG): Assertion failed: (mblength != (size_t)-1 && mblength != (size_t)-2), function inittables_mb, file /usr/src/gnu/usr.bin/sort/../../../contrib/gnu-sort/src/sort.c, line 706.

On my lab's server, a FreeBSD 9 box (9.0-BETA3 FreeBSD 9.0-BETA3 #40 
r226245: Tue Oct 11 10:01:29 CEST 2011), I receive for some ports while 
compiling this error:

Abort trap (core dumped)
Assertion failed: (mblength != (size_t)-1 && mblength != (size_t)-2), 
function inittables_mb, file 
/usr/src/gnu/usr.bin/sort/../../../contrib/gnu-sort/src/sort.c, line 706.

This just happened after the last update and reboot (did make world). Is 
this a bug? If yes, should I do a PR or is it already known? If not a 
bug, what is it?

Oliver