Enable the service runtime to use a zero-based sandbox on Linux.

src/trusted/service_runtime/build.scons

 # -*- python -*-
 # Copyright (c) 2011 The Native Client 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 platform
 import os
 
 Import('env')
 
@@ skipping 174 matching lines @@
 if env.Bit('linux'):
   ldr_inputs += ['posix/nacl_signal.c']
   if env.Bit('target_arm'):
     ldr_inputs += ['linux/nacl_signal_arm.c']
   elif env.Bit('target_x86_32'):
     ldr_inputs += ['linux/nacl_signal_32.c']
   elif env.Bit('target_x86_64'):
     ldr_inputs += ['linux/nacl_signal_64.c']
   else:
     raise Exception("Unsupported target")
+  env.Append(LIBS=['dl'])
 
 if env.Bit('mac'):
   ldr_inputs += ['posix/nacl_signal.c']
   if env.Bit('target_x86_32'):
     ldr_inputs += ['osx/nacl_signal_32.c']
   elif env.Bit('target_x86_64'):
     ldr_inputs += ['osx/nacl_signal_64.c']
   else:
     raise Exception("Unsupported target")
 
@@ skipping 593 matching lines @@
     expected_exit_status = 'sigabrt'
   node = env.CommandTest(
       'sel_ldr_thread_death_test.out',
       command=[sel_ldr_thread_death_test_exe],
       exit_status=expected_exit_status)
 
   # TODO(tuduce): Make it work on windows.
   env.AddNodeToTestSuite(node, ['medium_tests'],
                          'run_sel_ldr_thread_death_test',
                          is_broken=env.Bit('windows'))