Implement arflags in the GN build.

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")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
@@ skipping 144 matching lines @@
   } else if (is_android) {
     configs += [ "//build/config/android:compiler" ]
   } else if (is_linux) {
     configs += [ "//build/config/linux:compiler" ]
   } else if (is_nacl) {
     configs += [ "//build/config/nacl:compiler" ]
   } else if (is_ios || is_mac) {
     configs += [ "//build/config/mac:compiler" ]
   }
 
+  # Applies to all Posix systems.
+  if (is_posix) {
+    configs += [ "//build/config/posix:compiler" ]
+  }
+
   # See the definitions below.
   configs += [
     ":compiler_cpu_abi",
     ":compiler_codegen",
   ]
 
   # In general, Windows is totally different, but all the other builds share
   # some common GCC configuration.
   if (!is_win) {
     # Common GCC compiler flags setup.
@@ skipping 1252 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }