extension build tool for multiple PostgreSQL versions

 The postgresql-server-dev-all package provides the pg_buildext script for
 simplifying packaging of a PostgreSQL extension supporting multiple major
 versions of the product.
 .
 PostgreSQL is a fully featured object-relational database management
 system. It supports a large part of the SQL standard and is designed
 to be extensible by users in many aspects. Its features include ACID
 transactions, foreign keys, views, sequences, subqueries, triggers,
 outer joins, multiversion concurrency control, and user-defined types
 and functions.