DEPs-ing in tools/clang rather than relying on outdated scripts.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 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/android/config.gni")
 import("//build/config/chrome_build.gni")
 if (current_cpu == "arm") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
@@ skipping 831 matching lines @@
   # always have different versions. Certain flags may not be recognized by
   # one version or the other.
   if (!is_nacl) {
     # Flags NaCl (Clang 3.7) does not recognize.
     default_warning_flags += [
       # TODO(smklein): Enable this, crbug.com/507717
       "-Wno-shift-negative-value",
 
       # TODO(smklein): Consider enabling this once not broken by third party
       "-Wno-bitfield-width",
+
+      # TODO(smklein): Remove once not broken by base.
+      "-Wno-expansion-to-defined",
+
+      # TODO(smklein): Remove once not broken by third party.
+      "-Wno-constant-conversion",
     ]
   }
 }
 
 # chromium_code ---------------------------------------------------------------
 #
 # Toggles between higher and lower warnings for code that is (or isn't)
 # part of Chromium.
 
 config("chromium_code") {
@@ skipping 255 matching lines @@
   if (symbol_level == 0) {
     configs = [ ":no_symbols" ]
   } else if (symbol_level == 1) {
     configs = [ ":minimal_symbols" ]
   } else if (symbol_level == 2) {
     configs = [ ":symbols" ]
   } else {
     assert(false)
   }
 }