Build fails with gcc 9.4.0 after d3b1bb2

[mdboom]

Bug report

Bug description:

gcc-9.4.0 (from Ubuntu 20.04) fails to build latest CPython main:

In file included from ./Modules/_ctypes/callproc.c:87:
./Modules/_ctypes/ctypes.h:12:72: error: missing binary operator before token "("                                          12 | #   if USING_APPLE_OS_LIBFFI && defined(__has_builtin) && __has_builtin(__builtin_available)                          | 

The first bad commit seems to be d3b1bb2. Fix incoming.

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-129141: Fix build on gcc-9.4.0 #129142