[PATCH] Fix __has_{cpp_}attribute with -traditional-cpp (PR preprocessor/65238)

[Jason Merrill]

On 03/11/2015 03:10 PM, Jakub Jelinek wrote:
> __has_{cpp_,}attribute builtin macros are effectively function-like macros
> taking one argument (and the ISO preprocessor expands macros in the argument
> which is IMHO desirable), but the traditional preprocessor has been crashing
> on them or reporting errors.

Why do we want ISO preprocessor behavior in this specific situation?

Jason