QGIS and hard-coded PostgreSQL versions

[Jim Spath <jspath55%gmail.com@localhost>]

I have now built QGIS 3.44.11-Solothurn from pkgsrc 2026Q2 on systems
with PostgreSQL server and/or client versions from 14 to 18. I posted
about the older processor glitch earlier. I also built the wip QGIS
4.0.3-Norrköping on my faster machine.
If I try to add the package I built on one database version platform,
it will complain if a different version is installed. 3 and 4 act
similarly:

$ pkg_add ./qgis-4.0.3.tgz
pkg_add: no pkg found for 'postgresql16-client>=16.0nb1', sorry.
pkg_add: Can't install dependency postgresql16-client>=16.0nb1
pkg_add: Expected dependency postgresql16-client>=16.0nb1 still missing
pkg_add: 1 package addition failed
$  psql --version
psql (PostgreSQL) 18.4

The QGIS code does not appear to depend on specific PG database libraries.

$ ldd `which qgis` | grep -i sql
        -lQt6Sql.6 => /usr/pkg/qt6/lib/libQt6Sql.so.6
        -lsqlite3 => /usr/pkg/lib/libsqlite3.so

This has more impact than missing Python plug-ins as QGIS won't
install, much less run. It's likely there is a lot of infra behind
this I don't understand. So, an observation without a fix.

Jim