MFH: r369467

- Update to patchlevel 27 which changes how functions are exported.
  This should eliminate the recent vulnerabilities, but keep the
  requirement for --import-functions/IMPORTFUNCTIONS option for now.
- Loosen the --import-functions requirement so it is not needed when running
  an interactive shell. It is already disallowed for privileged/setuid mode.
- Show an error on stderr when an imported function is ignored.
Make sysutils/pstree operable in jailed environment.

(cherry picked from commit 0aa00da618ffa2bc5b4c4f8b89be22b9df2e9936)
Fixed replacement of $(PGBOUNCER_RUNDIR) in files/pgbouncer.in
Revert "Define and use "our_gid" variable."
Startup script now supports multiple profiles.

(cherry picked from commit bc186548d5f9d1b53d58e9abc5e39f7d916dba91)
(cherry picked from commit f7276b8fda49456743b97046b9f8ed6fb22cc8e2)