third_party: Add wayland library.

build/config/linux/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/linux/pkg_config.gni")
 import("//build/config/features.gni")
 import("//build/config/sysroot.gni")
 import("//build/config/ui.gni")
 
 # This is included by reference in the //build/config/compiler config that
@@ skipping 42 matching lines @@
 pkg_config("pangoft2") {
   packages = [ "pangoft2" ]
 }
 
 # Note: if your target also depends on //dbus, you don't need to add this
 # config (it will get added automatically if you depend on //dbus).
 pkg_config("dbus") {
   packages = [ "dbus-1" ]
 }
 
+pkg_config("libffi") {
+  packages = [ "libffi" ]
+}
+
 config("x11") {
   libs = [
     "X11",
     "Xcomposite",
     "Xcursor",
     "Xdamage",
     "Xext",
     "Xfixes",
     "Xi",
     "Xrender",
@@ skipping 68 matching lines @@
         "-Wno-unused-function",
       ]
     }
 
     pkg_config("gconf") {
       packages = [ "gconf-2.0" ]
       defines = [ "USE_GCONF" ]
     }
   }
 }