Makefile.in (STRICT2_WARN): Add @WERROR@.

        * Makefile.in (STRICT2_WARN): Add @WERROR@.
        (GCC_WARN_CFLAGS): Remove $(WERROR).
        (fixinc.sh-warn): New.
        * ada/Make-lang.in (ada-warn): Add $(WERROR).
        * cp/Make-lang.in (cp-warn): Add $(WERROR).
        * f/Make-lang.in (f-warn): Add $(WERROR).
        * java/Make-lang.in (java-warn): Add $(WERROR).
        * treelang/Make-lang.in (treelang-warn): Add $(WERROR).

From-SVN: r64606