meson: Add 'running' test setup, as a replacement for installcheck

meson: Add support for building with precompiled headers

windows: Adjust FD_SETSIZE via commandline define

meson: ecpg: Split definition of static and shared libraries

meson: docs: Add xml{lint,proc} wrapper to collect dependencies

ci: enable zstd where available.

ci: compile with -Og where applicable.

ci: include hints how to install OS packages.

ci: fix copy-paste mistake in 16eb8231d1b.

ci: macos: align sysinfo_script to other tasks.

plpython: add missing plpython.h include to plpy_plpymodule.h

plpython: Adjust docs after removal of Python 2 support.

plpython: Code cleanup related to removal of Python 2 support.

plpython: Remove regression test infrastructure for Python 2.

plpython: Remove plpythonu, plpython2u and associated transform extensions.

windows: Improve crash / assert / exception handling.

ci: windows: run tests under timeout.

Fix binary mismatch for MSVC plperl vs gcc built perl libs

Move parallel vacuum code to vacuumparallel.c.

Move index vacuum routines to vacuum.c.

Improve parallel vacuum implementation.

Fix parallel amvacuumcleanup safety bug.

windows: Remove use of WIN32_LEAN_AND_MEAN from crashdump.c.

Add module build directory to the PATH for TAP tests

Adapt src/test/ldap/t/001_auth.pl to work with openldap 2.5.