* c-opts.c (warn_variadic_macros): New.
        (c_common_handle_option): Set it.
        (sanitize_cpp_opts): Copy it to cpp_opts.
        * c.opt (Wvariadic-macros): New.
        * cpplib.h (struct cpp_options): Add warn_variadic_macros.
        * cppinit.c (cpp_create_reader): Initialize it.
        * cppmacro.c (parse_params): Check it.

From-SVN: r78125