The attached patch implements some changes that were discussed a
couple weeks ago on the hackers and interfaces lists:

1. When the backend sends a NOTICE message and closes the connection
   (typically, because it was told to by the postmaster after
   another backend coredumped), libpq will now print the notice
   and close the connection cleanly.  Formerly, the frontend app
   would usually terminate ungracefully due to a SIGPIPE.  (I am
   not sure if 6.3.2 behaved that way, but the current cvs sources
   do...)

2. libpq's various printouts to stderr are now fed through a single
   "notice processor" routine, which can be overridden by the
   application to direct notices someplace else.  This should ease
   porting libpq to Windows.

I also noticed and fixed a problem in PQprint: when sending output
to a pager subprocess, it would disable SIGPIPE in case the pager
terminates early (this is good) --- but afterwards it reset SIGPIPE
to SIG_DFL, rather than restoring the application's prior setting
(bad).

			regards, tom lane