[BUG] pg_ctl restart at the vanilla v8.3.4

When I run "pg_ctl restart" of the vanilla pgsql-8.3.4 without any options,
it does not work correctly.

-------- cut here --------
[kaigai(at)saba postgresql-8.3.4]$ ./root/bin/pg_ctl restart
LOG: received smart shutdown request
LOG: autovacuum launcher shutting down
waiting for server to shut down....LOG: shutting down
LOG: database system is shut down
done
server stopped
sh: -c: line 0: syntax error near unexpected token `null'
sh: -c: line 0: `"/home/kaigai/tmp/postgresql-8.3.4/root/bin/postgres" (null) < "/dev/null" 2>&1 &'
pg_ctl: could not start server: exit code was 512
[kaigai(at)saba postgresql-8.3.4]$
--------------------------

On pgsql-8.3.3, an empty string ("") is set to post_opts at read_post_opts()
when no command line options are given, but this code has gone at v8.3.4 and
NULL is remained.
This variable is used to make an argument of system() at start_postmaster(),
then /bin/sh claims it due to invalid command line.

Thanks,
--
OSS Platform Development Division, NEC
KaiGai Kohei <kaigai(at)ak(dot)jp(dot)nec(dot)com>