I have committed changes to pg_ctl.
1) postmaster.opts.default is being copied from
src/bin/pg_ctl/postmaster.opts.default.sample in the installation
procedure.
2) postmaster.opts.default is now installed by initdb.
3) The path to postmaster is determined in the runtime rather than
while creating pg_ctl script. That is a similar way to initdb
(actually codes stolen from it).
--
Tatsuo Ishii