Issue #21811: Anticipated fixes to 3.x and 2.7 for OS X 10.10 Yosemite.

tests/test_build_ext.py

@@ -444,8 +444,16 @@ class BuildExtTestCase(TempdirManager,
 
         # get the deployment target that the interpreter was built with
         target = sysconfig.get_config_var('MACOSX_DEPLOYMENT_TARGET')
-        target = tuple(map(int, target.split('.')))
-        target = '%02d%01d0' % target
+        target = tuple(map(int, target.split('.')[0:2]))
+        # 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:
+            # for 10.1 through 10.9.x -> "10n0"
+            target = '%02d%01d0' % target
+        else:
+            # for 10.10 and beyond -> "10nn00"
+            target = '%02d%02d00' % target
         deptarget_ext = Extension(
             'deptarget',
             [deptarget_c],