Add a get_random_bytes() syscall to replace the SRPC-based implementation

src/trusted/service_runtime/service_runtime.gyp

 # -*- gyp -*-
 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'conditions': [
       ['os_posix==1', {
         'syscall_handler': [
@@ skipping 57 matching lines @@
           'sel_qualify.c',
           'sel_validate_image.c',
           'sys_exception.c',
           'sys_fdio.c',
           'sys_filename.c',
           'sys_futex.c',
           'sys_imc.c',
           'sys_list_mappings.c',
           'sys_memory.c',
           'sys_parallel_io.c',
+          'sys_random.c',
           'thread_suspension_common.c',
           'thread_suspension_unwind.c',
         ],
         'include_dirs': [
           # For generated header files from the x86-64 validator,
           # e.g. nacl_disallows.h.
           '<(SHARED_INTERMEDIATE_DIR)',
         ],
         'sources!': [
            '<(syscall_handler)',
@@ skipping 380 matching lines @@
             }],
           ],
           'sources': [
             'linux/nacl_signal.c',
           ],
         },
       ],
     }],
   ],
 }