Fix most GN clang errors.

third_party/opus/BUILD.gn

 # Copyright 2014 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/arm.gni")
 
 # If fixed point implementation shall be used (otherwise float).
 use_opus_fixed_point = ((is_android || is_chromeos ||
                          (is_ios && arm_version == 7)) && cpu_arch == "arm")
 
@@ skipping 35 matching lines @@
   defines = [
     "OPUS_BUILD",
     "OPUS_EXPORT=",
   ]
 
   include_dirs = [
     "src/celt",
     "src/silk",
   ]
 
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
   direct_dependent_configs = [ ":opus_config" ]
 
   if (is_win) {
     defines += [
       "USE_ALLOCA",
       "inline=__inline",
     ]
 
     cflags = [
       "/wd4305",  # Disable truncation warning in celt/pitch.c .
@@ skipping 68 matching lines @@
       deps = [ ":convert_rtcd_assembler" ]
     }
   }
 }
 
 executable("opus_demo") {
   sources = [
     "src/src/opus_demo.c",
   ]
 
+  configs -= [ "//build/config/compiler:chromium_code" ]
+  configs += [ "//build/config/compiler:no_chromium_code" ]
+
   include_dirs = [
     "src/celt",
     "src/silk",
   ]
 
   if (is_win) {
     defines = [ "inline=__inline" ]
   }
   if (is_android) {
     libs = [ "log" ]
   }
 
   deps = [ ":opus" ]
 }