development files for Postgres-XC server-side programming

 Header files for compiling SSI code to link into Postgres-XC's backend; for
 example, for C functions to be called from SQL.
 .
 This package also contains the Makefiles necessary for building add-on
 modules of Postgres-XC, which would otherwise have to be built in the
 Postgres-XC source-code tree.
 .
 Postgres-XC is a write-scalable, synchronous multi-master, transparent
 PostgreSQL cluster.