GN: Add wexit_time_destructors config.

tools/gn/secondary/net/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("//crypto/ssl/flags.gni")
 import("//tools/grit/grit_rule.gni")
 
 component("net") {
   external = true
   sources = [
@@ skipping 1198 matching lines @@
     "server/http_connection.h",
     "server/http_server.cc",
     "server/http_server.h",
     "server/http_server_request_info.cc",
     "server/http_server_request_info.h",
     "server/http_server_response_info.cc",
     "server/http_server_response_info.h",
     "server/web_socket.cc",
     "server/web_socket.h",
   ]
+  configs += [ "//build/config/compiler:wexit_time_destructors" ]
   deps = [
     ":net",
     "//base",
   ]
-
-  # TODO(brettw) figure out how to get this:
-  # 'variables': { 'enable_wexit_time_destructors': 1, },
 }