distutils_spawn.py.patch

https://github.com/pypa/distutils/pull/36

diff --git a/distutils/spawn.py b/distutils/spawn.py
index a73b8b9..b012d00 100644
--- Lib/distutils/spawn.py
+++ Lib/distutils/spawn.py
@@ -60,13 +60,17 @@ def spawn(cmd, search_path=1, verbose=0, dry_run=0, env=None):
             if _cfg_target:
                 _cfg_target_split = [int(x) for x in _cfg_target.split('.')]
         if _cfg_target:
-            # ensure that the deployment target of build process is not less
-            # than that used when the interpreter was built. This ensures
-            # extension modules are built with correct compatibility values
+            # Ensure that the deployment target of the build process is not
+            # less than 10.3 if the interpreter was built for 10.3 or later.
+            # This ensures extension modules are built with correct
+            # compatibility values, specifically LDSHARED which can use
+            # '-undefined dynamic_lookup' which only works on >= 10.3.
             cur_target = os.environ.get('MACOSX_DEPLOYMENT_TARGET', _cfg_target)
-            if _cfg_target_split > [int(x) for x in cur_target.split('.')]:
+            cur_target_split = [int(x) for x in cur_target.split('.')]
+            if _cfg_target_split[:2] >= [10, 3] and cur_target_split[:2] < [10, 3]:
                 my_msg = ('$MACOSX_DEPLOYMENT_TARGET mismatch: '
-                          'now "%s" but "%s" during configure'
+                          'now "%s" but "%s" during configure;'
+                          'must use 10.3 or later'
                                 % (cur_target, _cfg_target))
                 raise DistutilsPlatformError(my_msg)
             env = dict(os.environ,