Add output directory argument to generate-unicode_norm_table.pl
This is in preparation for building postgres with meson / ninja.
When building with meson, commands are run at the root of the build tree. Add
an option to put build output into the appropriate place.
Author: Andres Freund <andres@anarazel.de>
Author: Peter Eisentraut <peter@eisentraut.org>
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/
5e216522-ba3c-f0e6-7f97-
5276d0270029@enterprisedb.com