make installcheck is broken in HEAD on mingw

"make installcheck" seems to be broken in HEAD on mingw for a few days,
though it ran sucessfully on Linux.

$ cd contrib/citext/
$ make installcheck
make -C ../../src/test/regress pg_regress.exe
make[1]: Entering directory `/d/projects/head/src/test/regress'
make[1]: `pg_regress.exe' is up to date.
make[1]: Leaving directory `/d/projects/head/src/test/regress'
../../src/test/regress/pg_regress --inputdir=. --psqldir=/usr/local/pgsql/bin --dbname=contrib_regression citext
(using postmaster on localhost, default port)
============== dropping database "contrib_regression" ==============
psql: FATAL: attempted change of parameter "port" ignored
DETAIL: This parameter cannot be changed after server start.
command failed: ""C:/mingw/local/pgsql/bin/psql" -X -c "DROP DATABASE IF EXISTS \"contrib_regression\"" "postgres""
make: *** [installcheck] Error 2

Regards,
---
ITAGAKI Takahiro
NTT Open Source Software Center