dbcommands.c

* removed a few redundant defines
* get_user_name safe under win32
* rationalized pipe read EOF for win32 (UPDATED PATCH USED)
* changed all backend instances of sleep() to pg_usleep

    - except for the SLEEP_ON_ASSERT in assert.c, as it would exceed a
32-bit long [Note to patcher: If a SLEEP_ON_ASSERT of 2000 seconds is
acceptable, please replace with pg_usleep(2000000000L)]

I added a comment to that part of the code:

    /*
     *  It would be nice to use pg_usleep() here, but only does 2000 sec
     *  or 33 minutes, which seems too short.
     */
    sleep(1000000);

Claudio Natoli