[cflags] Suppress -Wextra-semi in third party code

Bug: 56257
Change-Id: I79c530f11641f65983b5c67229a8b3b6fec128fb
Reviewed-on: https://fuchsia-review.googlesource.com/c/third_party/tink/+/604942
Fuchsia-Auto-Submit: Shai Barack <shayba@google.com>
Reviewed-by: Tamir Duberstein <tamird@google.com>
Commit-Queue: Shai Barack <shayba@google.com>
diff --git a/cc/BUILD.gn b/cc/BUILD.gn
index bca7b51..f842fc4 100644
--- a/cc/BUILD.gn
+++ b/cc/BUILD.gn
@@ -112,6 +112,7 @@
     "//third_party/tink/cc/util:statusor",
     "//third_party/tink/proto:tink_proto",
   ]
+  configs += [ "//build/config:Wno-extra-semi" ]
   public_configs = [ "//third_party/tink:tink_config" ]
 }