diff --git a/BUILD b/BUILD
index c02fb9d..642b6c4 100644
--- a/BUILD
+++ b/BUILD
@@ -438,6 +438,9 @@
     "//external:zlib",
     ":gpr",
   ],
+  copts = [
+    "-std=gnu99",
+  ],
 )
 
 
@@ -707,6 +710,9 @@
   deps = [
     ":gpr",
   ],
+  copts = [
+    "-std=gnu99",
+  ],
 )