Improve run-time diagnostic for "PRINT '(I1', 42":

        * com.c (ffecom_char_args_x_): Renamed from ffecom_char_args_,
        which is now a macro (to avoid lots of changes to other code)
        with new arg, ffecom_char_args_with_null_ being another new
        macro to call same function with different value for new arg.
        This function now appends a null byte to opCONTER expression
        if the new arg is TRUE.
        (ffecom_arg_ptr_to_expr): Support NULL length pointer.
        * ste.c (ffeste_io_cilist_):
        (ffeste_io_icilist_): Pass NULL length ptr for
        FORMAT expression, so null byte gets appended where
        feasible.
        * target.c (ffetarget_character1):
        (ffetarget_concatenate_character1):
        (ffetarget_substr_character1):
        (ffetarget_convert_character1_character1):
        (ffetarget_convert_character1_hollerith):
        (ffetarget_convert_character1_integer4):
        (ffetarget_convert_character1_logical4):
        (ffetarget_convert_character1_typeless):
        (ffetarget_hollerith): Append extra phantom null byte as
        part of FFETARGET-NULL-BYTE kludge.
Yes, even more patches from Craig :-)

From-SVN: r18187