backports/postgresql15: new aport

backports/postgresql15/postgresql15.post-install

@@ -0,0 +1,12 @@
+#!/bin/sh
+
+majorver=${1%%.*}
+
+cat >&2 <<EOF
+*
+* If you want to use JIT in PostgreSQL, install postgresql$majorver-jit or
+* postgresql-jit (if you didn't install specific major version of postgresql).
+*
+EOF
+
+exit 0