[cpp] Suppress -Wetra-semi in third party code

Bug: 56257
Change-Id: Ib348a7bc74b7fa39fde1157bd21401d1f65fd80c
diff --git a/BUILD.gn b/BUILD.gn
index 0802801..64593e7 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -16,6 +16,7 @@
     deps += [ "src/warm:Warm" ]
   }
   configs += [ "//third_party/openweave-core/src/include:fuchsia" ]
+  configs += [ "//build/config:Wno-extra-semi" ]
   public_configs = [ "//third_party/openweave-core/src/include:public" ]
   public_deps = [ "//third_party/openweave-core/src/include:common" ]
 }