Bothptrack engine and public SQL API are now inside extension. Only
certain required hooks have been left as a PostgreSQL core patch.

Also many things have changed since 2.0.0:

• Fixed many compatibility bugs: alignment issues with atomics usage on Win32,
  with atomics simulation via spinlocks.
• Added versioning into theptrack map.
• Added automated standalone testing withpg_probackup via travis-ci in
  different modes, including a 'legacy' mode, i.e. withEXEC_BACKEND
  and--disable-atomics.
• Removedpg_ptrack_get_block.

Upgrading from 2.0.0:

• Putshared_preload_libraries = 'ptrack' intopostgresql.conf.
• Renameptrack_map_size toptrack.map_size.
• DoALTER EXTENSION 'ptrack' UPDATE;.
• Restart server.