Update postgresql-plr to version 8.4.7 / rev 8 via SR 1245886
    
    https://build.opensuse.org/request/show/1245886
    by user rmax + anag+factory
    - Stop building for EOL postgresql12.
    
    - update patch-Makefile-ldflags.patch
    - update to bugfix release 8.4.7 adding support to postgresql17
      - remove calls to tuplestore_donestoring(tupstore) this was a
        macro which was defined as a no-op it was removed in postgres
        commit postgres/postgres@75680c3
      - fix some warnings of uninitialized variables (#158)