On Fri, 12 May 2023, 07:02 Po Lu via Gcc, <gcc@gcc.gnu.org> wrote:

> Jason Merrill <jason@redhat.com> writes:
>
> > You shouldn't have to change any of those, just configure with CC="gcc
> > -fwhatever".
>
> If it were so simple...
>
> Many Makefiles come with a habit of using not CC_FOR_BUILD, but just
> `cc', to build programs which are run on the build machine.
>
> These programs are intended to be as portable as possible (naturally,
> since Autoconf does not configure for the build machine).  As a result,
> they are typically written in the subset of ANSI C that will compile
> with almost any C compiler, which is exactly what will cause problems
> with GCC's proposed new defaults.
>

Then they should not use implicit int and implicit function declarations.

You've made your opinion clear. It has been noted.