bpo-41100: additional fixes for testing on macOS 11 Big Sur Intel

Note: macOS 11 is not yet released, this release of Python is not
fully supported on 11.0, and not all tests pass.

Lib/distutils/tests/test_build_ext.py

@@ -470,7 +470,7 @@ class BuildExtTestCase(TempdirManager,
         # format the target value as defined in the Apple
         # Availability Macros.  We can't use the macro names since
         # at least one value we test with will not exist yet.
-        if target[1] < 10:
+        if target[:2] < (10, 10):
             # for 10.1 through 10.9.x -> "10n0"
             target = '%02d%01d0' % target
         else:

Lib/test/test_platform.py

@@ -236,6 +236,11 @@ class PlatformTest(unittest.TestCase):
             fd.close()
             self.assertFalse(real_ver is None)
             result_list = res[0].split('.')
+            # macOS 11.0 (Big Sur) may report its version number
+            # as 10.16 if the executable is built with an older
+            # SDK target but sw_vers reports 11.0.
+            if result_list == ['10', '16']:
+                result_list = ['11', '0']
             expect_list = real_ver.split('.')
             len_diff = len(result_list) - len(expect_list)
             # On Snow Leopard, sw_vers reports 10.6.0 as 10.6

Misc/NEWS.d/next/macOS/2020-08-15-00-33-27.bpo-41100.AksBg1.rst

@@ -0,0 +1,3 @@
+Additional fixes for testing on macOS 11 Big Sur Intel. Note: macOS 11 is
+not yet released, this release of Python is not fully supported on 11.0, and
+not all tests pass.

Modules/getpath.c

@@ -566,11 +566,7 @@ calculate_program_full_path(const _PyCoreConfig *core_config,
     memset(program_full_path, 0, sizeof(program_full_path));
 
 #ifdef __APPLE__
-#if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4
     uint32_t nsexeclength = MAXPATHLEN;
-#else
-    unsigned long nsexeclength = MAXPATHLEN;
-#endif
     char execpath[MAXPATHLEN+1];
 #endif
 

configure

@@ -9251,6 +9251,9 @@ fi
     	ppc)
     		MACOSX_DEFAULT_ARCH="ppc64"
     		;;
+    	arm64)
+    		MACOSX_DEFAULT_ARCH="arm64"
+    		;;
     	*)
     		as_fn_error $? "Unexpected output of 'arch' on OSX" "$LINENO" 5
     		;;

configure.ac

@@ -2456,6 +2456,9 @@ case $ac_sys_system/$ac_sys_release in
     	ppc)
     		MACOSX_DEFAULT_ARCH="ppc64"
     		;;
+    	arm64)
+    		MACOSX_DEFAULT_ARCH="arm64"
+    		;;
     	*)
     		AC_MSG_ERROR([Unexpected output of 'arch' on OSX])
     		;;