These are simple space-separated key-value pair sets of options instead of the
URI style DSNs, but they are also much more flexible allowing the user to
specify client SSL certificates, server certificates, compression and
encryption levels, and much more (see [1] for more information)
[1]: https://www.postgresql.org/docs/9.1/libpq-connect.html
Changelog-Added: db: Added support for key-value DSNs for postgresql, allowing for a wider variety of configurations and environments.
And rename them so they're not cleared by `make clean`. We leave the
old rules in place so old files get cleaned still.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Fixed: build: On some operating systems the postgresql library would not get picked up. `./configure` now uses `pg_config` to locate the headers.