[fuchsia] Make the dependency on runtime library explicit

runtime/vm/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.
 
 config("libdart_vm_config") {
   # TODO(zra, jamesr): This check can go away after some problems with the
   # fuchsia toolchain definition are fixed.
   if (!defined(is_fuchsia) || !is_fuchsia) {
     libs = [ "dl" ]
 
     if (!is_android) {
       libs += [ "pthread" ]
 
       if (is_linux) {
         libs += [ "rt" ]
       }
     }
+  } else {
+    libs = [ "runtime" ]
   }
 }
 
 
 static_library("libdart_platform") {
   configs += ["..:dart_config", "..:dart_product_config"]
   public_configs = [":libdart_vm_config"]
 
   platform_headers_gypi =
       exec_script("../../tools/gypi_to_gn.py",
@@ skipping 196 matching lines @@
     ["developer", "developer", true, "../../sdk/lib/developer", "../lib"],
     ["_internal", "internal", true, "../../sdk/lib/internal", "../lib"],
     ["isolate", "isolate", true, "../../sdk/lib/isolate", "../lib"],
     ["math", "math", true, "../../sdk/lib/math", "../lib"],
     ["mirrors", "mirrors", true, "../../sdk/lib/mirrors", "../lib"],
     ["profiler", "profiler", false, "../../sdk/lib/profiler"],
     ["typed_data", "typed_data", false, "../lib"],
     ["_vmservice", "vmservice", true, "../../sdk/lib/vmservice", "../lib"],
   ]
 }