Merge pull request #20451 from veblush/py-win

Fix python windows link problem

setup.py

@@ -147,7 +147,8 @@ EXTRA_ENV_COMPILE_ARGS = os.environ.get('GRPC_PYTHON_CFLAGS', None)
 EXTRA_ENV_LINK_ARGS = os.environ.get('GRPC_PYTHON_LDFLAGS', None)
 if EXTRA_ENV_COMPILE_ARGS is None:
   EXTRA_ENV_COMPILE_ARGS = ' -std=c++11'
-  if 'win32' in sys.platform and sys.version_info < (3, 5):
+  if 'win32' in sys.platform:
+    if sys.version_info < (3, 5):
       EXTRA_ENV_COMPILE_ARGS += ' -D_hypot=hypot'
       # We use define flags here and don't directly add to DEFINE_MACROS below to
       # ensure that the expert user/builder has a way of turning it off (via the
@@ -157,6 +158,10 @@ if EXTRA_ENV_COMPILE_ARGS is None:
         EXTRA_ENV_COMPILE_ARGS += ' -D_ftime=_ftime32 -D_timeb=__timeb32 -D_ftime_s=_ftime32_s'
       else:
         EXTRA_ENV_COMPILE_ARGS += ' -D_ftime=_ftime64 -D_timeb=__timeb64'
+    else:
+      # We need to statically link the C++ Runtime, only the C runtime is
+      # available dynamically
+      EXTRA_ENV_COMPILE_ARGS += ' /MT'
   elif "linux" in sys.platform:
     EXTRA_ENV_COMPILE_ARGS += ' -std=gnu99 -fvisibility=hidden -fno-wrapv -fno-exceptions'
   elif "darwin" in sys.platform: