Martin,
Thank you for the feedback.

I think we can avoid the problem that would be introduced by the removal
of Py_GCC_ATTRIBUTE by leaving it as is
(probably adding "#warning this macro is deprecated. Please use
Py_GCC_FORMAT_ATTRIBUTE instead").

The patch looks not so complicated to me. It's just a renaming of a
macro. The new name is more explicit.

IMHO, source code should be kept warning-free, as long as the fix is
simple and it does not cost much.

So I think now the question would be whether having explicitly named
macro and warning-free code for old compilers worth the effort of
renaming all Py_GCC_ATTRIBUTE to Py_GCC_FORMAT_ATTRIBUTE.

I would like to leave the decision to the core developers.