Buildfarm failure - pl/tcl on snake

CVS HEAD is consistently failing on snake in pl/tcl, whilst
REL8_0_STABLE is passing just fine.

select * from T_pkey1 order by key1 using @<, key2;
key1 | key2 | txt

------+----------------------+------------------------------------------
- 1 | KEY1-3 | should work

1 | key1-1 | test key

1 | key1-2 | test key

1 | key1-3 | test key

2 | key2-3 | test key

2 | key2-9 | test key

(6 rows)
--- 166,175 ----
select * from T_pkey1 order by key1 using @<, key2;
key1 | key2 | txt

------+----------------------+------------------------------------------
1 | key1-1 | test key

1 | key1-2 | test key

1 | key1-3 | test key

+ 1 | KEY1-3 | should work

2 | key2-3 | test key

2 | key2-9 | test key

(6 rows)

Loris, the only other Win32 box with TCL, is green. Does anyone know
what might be causing this?

Regards, Dave.