Move snowball_create.sql creation into perl file
This is in preparation for building postgres with meson / ninja.
We already have duplicated code for this between the make and msvc
builds. Adding a third copy seems like a bad plan, thus move the generation
into a perl script.
As we don't want to rely on perl being available for builds from tarballs,
generate the file during distprep.
Author: Peter Eisentraut <peter@eisentraut.org>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/
5e216522-ba3c-f0e6-7f97-
5276d0270029@enterprisedb.com