Cannot initdb in cvs tip

I'm getting the following error when trying to initdb with CVS tip. This
is on win XP, though I don't know if it's win32 specific. Also of note,
although it says it's clearing the contents of the directory, in actual
fact it leaves the directory structure in place, thus a subsequent
initdb will not run without a manual clearup.

Regards, Dave.

$ initdb
The files belonging to this database system will be owned by user
"dpage".
This user must also own the server process.

The database cluster will be initialized with locale English_United
Kingdom.1252 .

fixing permissions on existing directory C:/msys/1.0/local/pgsql/data
... ok
creating directory C:/msys/1.0/local/pgsql/data/global ... ok
creating directory C:/msys/1.0/local/pgsql/data/pg_xlog ... ok
creating directory C:/msys/1.0/local/pgsql/data/pg_clog ... ok
creating directory C:/msys/1.0/local/pgsql/data/base ... ok
creating directory C:/msys/1.0/local/pgsql/data/base/1 ... ok
creating directory C:/msys/1.0/local/pgsql/data/pg_tablespaces ... ok
selecting default max_connections ... 100
selecting default shared_buffers ... 1000
creating configuration files ... ok
creating template1 database in C:/msys/1.0/local/pgsql/data/base/1 ...
ERROR: could not open segment 1 of relation 1663/1/1255 (target block
26189776): No such file or directory
Deleted file - C:\msys\1.0\local\pgsql\data\pg_hba.conf
Deleted file - C:\msys\1.0\local\pgsql\data\pg_ident.conf
Deleted file - C:\msys\1.0\local\pgsql\data\PG_VERSION
Deleted file - C:\msys\1.0\local\pgsql\data\postgresql.conf
Deleted file - C:\msys\1.0\local\pgsql\data\base\1\1255
Deleted file - C:\msys\1.0\local\pgsql\data\global\pg_control
Deleted file - C:\msys\1.0\local\pgsql\data\pg_clog\0000
Deleted file - C:\msys\1.0\local\pgsql\data\pg_xlog\0000000000000000
child process was terminated by signal 1
initdb.exe: failed
initdb.exe: removing contents of data directory
"C:/msys/1.0/local/pgsql/data"
$