2016-09-30  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * configure.ac: Split CHECKING_P into CHECKING_P and
        ENABLE_EXTRA_CHECKING.
        * configure: Regenerated.
        * config.in: Adjust commment of CHECKING_P.  Add ENABLE_EXTRA_CHECKING.
        * common.opt (flag_checking): Use CHECKING_P and ENABLE_EXTRA_CHECKING.

From-SVN: r240677