re PR plugins/52872 (--enable-plugin; incorrect test for "exported symbols" and "-rdynamic" in gcc/configure.ac)

        PR plugin/52862
        * configure.ac: Adding for exported symbols check
        and for rdynamic-check executable-extension.
        * configure: Regenerated.

Co-Authored-By: Kai Tietz <ktietz@redhat.com>

From-SVN: r204650