Gcc: Suppress warnings in third_party

third_party/libxml/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.
 
 # Define an "os_include" variable that points at the OS-specific generated
 # headers.  These were generated by running the configure script offline.
 if (is_linux || is_android || is_nacl) {
   os_include = "linux"
 } else if (is_mac || is_ios) {
   os_include = "mac"
@@ skipping 42 matching lines @@
       "-Wno-int-to-void-pointer-cast",
 
       # libxml passes a volatile LPCRITICAL_SECTION* to a function expecting
       # a void* volatile*.
       "-Wno-incompatible-pointer-types",
 
       # trio_is_special_quantity and trio_is_negative are only
       # used with certain preprocessor defines set.
       "-Wno-unused-function",
     ]
+  } else if (is_linux) {
+    cflags = [
+      # gcc spits out a bunch of warnings about passing too many arguments to
+      # __xmlSimpleError.
+      "-Wno-format-extra-args",
+    ]
   }
 }
 
 static_library("libxml") {
   output_name = "libxml2"
   sources = [
     "chromium/libxml_utils.cc",
     "chromium/libxml_utils.h",
     "linux/config.h",
     "linux/include/libxml/xmlversion.h",
@@ skipping 128 matching lines @@
   if (is_mac || is_ios || is_android) {
     # http://www.xmlsoft.org/threads.html says that this is required when using
     # libxml from several threads, which can possibly happen in chrome. On
     # linux, this is picked up by transitivity from pkg-config output from
     # build/linux/system.gyp.
     defines = [ "_REENTRANT" ]
   }
 
   include_dirs = [ "$os_include" ]
 }