Allow building mojo_shell and non-graphical apps/services on a Mac

gpu/config/BUILD.gn

 # Copyright 2014 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/ui.gni")
 
 declare_args() {
   # Use the PCI lib to collect GPU information on Linux.
   use_libpci = true
 }
@@ skipping 78 matching lines @@
     deps += [
       "//third_party/libXNVCtrl",
       "//ui/gfx/x",
     ]
   } else {
     sources -= [ "gpu_info_collector_x11.cc" ]
   }
   if (!use_ozone) {
     sources -= [ "gpu_info_collector_ozone.cc" ]
   }
+  if (is_mac) {
+    cflags = [ "-Wno-deprecated-declarations" ]
+  }
 }