Remove pgrminclude and associated scripts
Per git log, the last time someone tried to do something with
pgrminclude was around 2011. And it's always had a tendency of
causing trouble when it was active. Also, pgcominclude is redundant
with headerscheck.
Discussion: https://www.postgresql.org/message-id/flat/
2d4dc7b2-cb2e-49b1-b8ca-
ba5f7024f05b%40eisentraut.org