All the ERROR_* fields are removed in favor of a more simple layer
made of ERROR, FATAL, PANIC. The two last ones are not actually used
yet, thought there should be some code paths that would need more
polishing on this matter.
The error message emitted before leaving should be fine to let the
user know what is happening.
--debug and --verbose had actually the same meaning as they were aimed
at giving to the user information regarding how the process is running,
hence both options are merged into --verbose and use elog(LOG) to decide
if a given message should be printed out depending on the verbosity of
the call. This makes a couple of routines more readable as they do not
depend on any boolean checks.
The "_()" have been removed from the code, those are aimed at being used
for translation but having them mandatorily in each log message is just
useless noise. If needed, pgut.c should be updated in consequence to
have a more portable facility.
At the same time this commit takes care of putting into correct shape
some code paths more in-line with PostgreSQL policy. There are surely
more of this kind of ugly stuff but at this stage things are more simple
and more manageable.
The system function used up to now was pg_xlogfile_name_offset, which
cannot be used on a node in recovery, and it was the only way present
to fetch the timeline ID of a backup, either incremental or full. So
instead scan the control file of server and fetch the timeline from
that. This also removes the restriction on which a backup could not
be taken on a standby node. The next step being to have the possibility
to take backups from streams.
