Backport of r52233

Lib/distutils/sysconfig.py

@@ -509,7 +509,11 @@ def get_config_vars(*args):
                 # are in CFLAGS or LDFLAGS and remove them if they are.
                 # This is needed when building extensions on a 10.3 system
                 # using a universal build of python.
-                for key in ('LDFLAGS', 'BASECFLAGS'):
+                for key in ('LDFLAGS', 'BASECFLAGS',
+                        # a number of derived variables. These need to be
+                        # patched up as well.
+                        'CFLAGS', 'PY_CFLAGS', 'BLDSHARED'):
+
                     flags = _config_vars[key]
                     flags = re.sub('-arch\s+\w+\s', ' ', flags)
                     flags = re.sub('-isysroot [^ \t]*', ' ', flags)