GN: Use build directory for CD for scripts

tools/gn/secondary/base/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.
 
 config("base_libs") {
   if (!is_win) {
     ldflags = [ "-ldl" ]
   }
 }
 
@@ skipping 303 matching lines @@
     "message_loop/message_pump_io_ios.h",
     "message_loop/message_pump_libevent.cc",
     "message_loop/message_pump_libevent.h",
     "message_loop/message_pump_mac.h",
     "message_loop/message_pump_mac.mm",
     "message_loop/message_pump_observer.h",
     "message_loop/message_pump_ozone.cc",
     "message_loop/message_pump_ozone.h",
     "message_loop/message_pump_win.cc",
     "message_loop/message_pump_win.h",
+    "message_loop/message_pump_x11.cc",
+    "message_loop/message_pump_x11.h",
     "metrics/field_trial.cc",
     "metrics/field_trial.h",
     "metrics/sample_map.cc",
     "metrics/sample_map.h",
     "metrics/sample_vector.cc",
     "metrics/sample_vector.h",
     "metrics/bucket_ranges.cc",
     "metrics/bucket_ranges.h",
     "metrics/histogram.cc",
     "metrics/histogram.h",
@@ skipping 676 matching lines @@
 static_library("run_all_unittests") {
   external = true
   sources = [
     "test/run_all_unittests.cc",
   ]
   deps = [
     ":test_support_base",
   ]
 }