Force the Python host version on Mac OS X

setup.py

@@ -30,10 +30,12 @@
 """A setup module for the GRPC Python package."""
 
 from distutils import extension as _extension
+from distutils import util
 import os
 import os.path
 import pkg_resources
 import platform
+import re
 import shlex
 import shutil
 import sys
@@ -133,6 +135,10 @@ if 'darwin' in sys.platform and PY3:
   if mac_target and (pkg_resources.parse_version(mac_target) <
                      pkg_resources.parse_version('10.7.0')):
     os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.7'
+    os.environ['_PYTHON_HOST_PLATFORM'] = re.sub(
+        r'macosx-[0-9]+\.[0-9]+-(.+)',
+        r'macosx-10.7-\1',
+        util.get_platform())
 
 
 def cython_extensions(module_names, extra_sources, include_dirs,

tools/distrib/python/grpcio_tools/setup.py

@@ -28,11 +28,13 @@
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 from distutils import extension
+from distutils import util
 import errno
 import os
 import os.path
 import pkg_resources
 import platform
+import re
 import shlex
 import shutil
 import sys
@@ -83,6 +85,10 @@ if 'darwin' in sys.platform and PY3:
   if mac_target and (pkg_resources.parse_version(mac_target) <
 		     pkg_resources.parse_version('10.9.0')):
     os.environ['MACOSX_DEPLOYMENT_TARGET'] = '10.9'
+    os.environ['_PYTHON_HOST_PLATFORM'] = re.sub(
+        r'macosx-[0-9]+\.[0-9]+-(.+)',
+        r'macosx-10.9-\1',
+        util.get_platform())
 
 def package_data():
   tools_path = GRPC_PYTHON_TOOLS_PACKAGE.replace('.', os.path.sep)