opt-functions.awk (lang_enabled_by): Support || for enabled-by.

opt-functions.awk (lang_enabled_by): Support || for enabled-by.

2014-11-29  Tobias Burnus  <burnus@net-b.de>
            Manuel López-Ibáñez  <manu@gcc.gnu.org>

gcc/
        * opt-functions.awk (lang_enabled_by): Support || for
        enabled-by.
        * optc-gen.awk: Ditto.
        * doc/options.texi (LangEnabledBy, EnabledBy): Document the
        || syntax.

gcc/fortran/
        * lang.opt (Wtabs): Combine duplicated item into a single
        one using || for LangEnabledBy.

Co-Authored-By: Manuel López-Ibáñez <manu@gcc.gnu.org>
From-SVN: r218175