Fix OAuth and Realtime issues introduced in 9a515b9234
[DATABASE] Fix an empty default value mistake introduced in
fde929b151
[DATABASE][PostgreSQL] Avoid use of pg_constraint.consrc, which was removed in
PostgreSQL 12.
[DATABASE][MariaDB] Fix a typo introduced in aed2344bd4
[DAEMON] Wrap an assignment inside "switch":
a follow-up to adc689cb15
lib/plugin.php now has a parent onAutoload function that finds most common
files that are used in plugins (actions, dataobjects, forms, libs etc.) if
they are put in the standardised directories ('actions', 'classes', 'forms',
'lib' and perhaps some others in the future).
