New header varatt.h split off from postgres.h
This new header contains all the variable-length data types support
(TOAST support) from postgres.h, which isn't needed by large parts of
the backend code.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/
ddcce239-0f29-6e62-4b47-
1f8ca742addf%40enterprisedb.com