When I just comment out the 

#include "pyatomic.h" 

line, python 3.5.0 will no longer compile

gcc -pthread -c -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes    -Werror=declaration-after-statement   -I. -IInclude -I./Include    -DPy_BUILD_CORE -o Programs/python.o ./Programs/python.c
In file included from Include/traceback.h:8:0,
                 from Include/Python.h:97,
                 from ./Programs/python.c:3:
Include/pystate.h:186:8: error: unknown type name ‘_Py_atomic_address’
 PyAPI_DATA(_Py_atomic_address) _PyThreadState_Current;
        ^
Makefile:747: recipe for target 'Programs/python.o' failed
make: *** [Programs/python.o] Error 1

pystate.h:

/* Assuming the current thread holds the GIL, this is the
   PyThreadState for the current thread.

   Issue #23644: pyatomic.h is incompatible with C++ (yet). Disable
   PyThreadState_GET() optimization: declare it as an alias to
   PyThreadState_Get(), as done for limited API. */
#if !defined(Py_LIMITED_API) && !defined(__cplusplus)
PyAPI_DATA(_Py_atomic_address) _PyThreadState_Current;
#endif