bpo-32592: Set Windows 8 as the minimum required version for API support (GH-15951)

Misc/NEWS.d/next/Windows/2019-09-11-14-51-56.bpo-32592.jvQMD9.rst

+Set Windows 8 as the minimum required version for API support

Modules/posixmodule.c

@@ -12204,8 +12204,6 @@ os_cpu_count_impl(PyObject *module)
 {
     int ncpu = 0;
 #ifdef MS_WINDOWS
-    /* Declare prototype here to avoid pulling in all of the Win7 APIs in 3.8 */
-    DWORD WINAPI GetActiveProcessorCount(WORD group);
     ncpu = GetActiveProcessorCount(ALL_PROCESSOR_GROUPS);
 #elif defined(__hpux)
     ncpu = mpctl(MPC_GETNUMSPUS, NULL, NULL);

PC/pyconfig.h

@@ -135,9 +135,9 @@ WIN32 is still required for the locale module.
 #endif /* MS_WIN64 */
 
 /* set the version macros for the windows headers */
-/* Python 3.5+ requires Windows Vista or greater */
-#define Py_WINVER 0x0600 /* _WIN32_WINNT_VISTA */
-#define Py_NTDDI NTDDI_VISTA
+/* Python 3.9+ requires Windows 8 or greater */
+#define Py_WINVER 0x0602 /* _WIN32_WINNT_WIN8 */
+#define Py_NTDDI NTDDI_WIN8
 
 /* We only set these values when building Python - we don't want to force
    these values on extensions, as that will affect the prototypes and