Begin work on ios secure sockets

runtime/bin/BUILD.gn

 # Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 
 declare_args() {
   dart_io_support = false
 }
 
 
@@ skipping 262 matching lines @@
   ]
   if (!is_mac && !is_ios) {
     # Dart tree uses *_macos.* instead of *_mac.*
     custom_sources_filter += [
       "*_macos.h",
       "*_macos.cc",
     ]
   }
   set_sources_assignment_filter(custom_sources_filter)
 
-  defines = [ "DART_IO_SECURE_SOCKET_DISABLED" ]
+  if (is_mac || is_ios) {
+    libs = [
+      "Security.framework",
+    ]
+  } else {
+    defines = [ "DART_IO_SECURE_SOCKET_DISABLED" ]
+  }
 
   sources = io_impl_sources_gypi.sources + builtin_impl_sources_gypi.sources
   sources += [
     "builtin_nolib.cc",
     "builtin_natives.cc",
     "io_natives.cc",
     "io_natives.h",
     "embedded_dart_io.cc",
     "embedded_dart_io.h",
     "log_android.cc",
     "log_linux.cc",
     "log_macos.cc",
     "log_win.cc",
     "log.h",
   ]
 
   include_dirs = [
     "..",
     "//third_party"
   ]
 }