Fix Python
diff --git a/setup.py b/setup.py
index b370be6..69e59e3 100644
--- a/setup.py
+++ b/setup.py
@@ -97,6 +97,7 @@
 DEFINE_MACROS = (('OPENSSL_NO_ASM', 1), ('_WIN32_WINNT', 0x600), ('GPR_BACKWARDS_COMPATIBILITY_MODE', 1),)
 
 LDFLAGS = ()
+CFLAGS = ()
 if "linux" in sys.platform:
   LDFLAGS += ('-Wl,-wrap,memcpy',)
 if "linux" in sys.platform or "darwin" in sys.platform: