
This commit doesn't actually add anything that uses ZSTD; that will be done separately. It just puts the basic infrastructure into place. Jeevan Ladhe, Robert Haas, and Michael Paquier. Reviewed by Justin Pryzby and Andres Freund. Discussion: http://postgr.es/m/CA+TgmoatQKGd+8SjcV+bzvw4XaoEwminHjU83yG12+NXtQzTTQ@mail.gmail.com