Perform provider-specific initialization in new functions.

Reviewed-by: Andreas Karlsson
Discussion: https://postgr.es/m/4548a168-62cd-457b-8d06-9ba7b985c477@proxel.se

src/backend/utils/adt/meson.build

@@ -66,6 +66,7 @@ backend_sources += files(
   'orderedsetaggs.c',
   'partitionfuncs.c',
   'pg_locale.c',
+  'pg_locale_builtin.c',
   'pg_locale_icu.c',
   'pg_locale_libc.c',
   'pg_lsn.c',