[PING c, c++, fortran, treelang] remove signed(_or_unsigned)?_type langhooks

[Tobias Schlüter]

Rafael Espindola wrote:
>       * gcc/fortran/trans-types.c (gfc_signed_type): Remove.
>       * gcc/fortran/trans-types.h (gfc_signed_type): Remove.
>       * gcc/fortran/f95-lang.c (LANG_HOOKS_SIGNED_TYPE): Remove.

These are ok.

- Tobi