Fix iOS GN build and cleanup system_wrappers

webrtc/common_audio/BUILD.gn

 # Copyright (c) 2014 The WebRTC project authors. All Rights Reserved.
 #
 # Use of this source code is governed by a BSD-style license
 # that can be found in the LICENSE file in the root of the source
 # tree. An additional intellectual property rights grant can be found
 # in the file PATENTS.  All contributing project authors may
 # be found in the AUTHORS file in the root of the source tree.
 
 import("//build/config/arm.gni")
 import("../build/webrtc.gni")
@@ skipping 221 matching lines @@
     # TODO(fdegans): Enable this. See crbug.com/408997.
     if (rtc_use_lto) {
       cflags -= [
         "-flto",
         "-ffat-lto-objects",
       ]
     }
 
     configs += [ "..:common_config" ]
     public_configs = [ "..:common_inherited_config" ]
+
+    if (is_clang) {
+      # Suppress warnings from Chrome's Clang plugins.
+      # See http://code.google.com/p/webrtc/issues/detail?id=163 for details.
+      configs -= [ "//build/config/clang:find_bad_constructs" ]
+    }
   }
 }