diff --git a/grpc.BUILD b/grpc.BUILD
index 2579536b17a457..624079a0c7be1f 100644
--- a/grpc.BUILD
+++ b/grpc.BUILD
@@ -1558,6 +1558,9 @@ cc_library(
     ":grpc",
     ":gpr",
   ],
+  copts = [
+    "-std=gnu99",
+  ],
 )