[MIPS] Add MIPS trusted toolchain to toolchain_revisions

SConstruct

 #! -*- python -*-
 # 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.
 
 import atexit
 import json
 import os
 import platform
 import re
@@ skipping 2740 matching lines @@
   if env.Bit('built_elsewhere'):
     def FakeInstall(dest, source, env):
       print 'Not installing', dest
       # Replace build commands with no-ops
     env.Replace(CC='true', CXX='true', LD='true',
                 AR='true', RANLIB='true', INSTALL=FakeInstall)
   else:
     tc_dir = os.path.join(jail, 'bin')
     if not which(os.path.join(tc_dir, 'mipsel-linux-gnu-gcc')):
       raise UserError("\nERRROR: "
-          "MIPS trusted TC is not installed - try running:\n"
-          "tools/trusted_cross_toolchains/trusted-toolchain-creator"
+          "MIPS trusted toolchain not found - try running:\n"
+          "  build/package_version/package_version.py --packages"
+          " linux_x86/mips_trusted sync -x\n"
+          "Or build it yourself with:\n"
+          "  tools/trusted_cross_toolchains/trusted-toolchain-creator"
           ".mipsel.debian.sh nacl_sdk")
     env.Replace(CC=os.path.join(tc_dir, 'mipsel-linux-gnu-gcc'),
                 CXX=os.path.join(tc_dir, 'mipsel-linux-gnu-g++'),
                 LD=os.path.join(tc_dir, 'mipsel-linux-gnu-ld'),
                 ASFLAGS=[],
                 LIBPATH=['${LIB_DIR}',
                          jail + '/sysroot/usr/lib']
                 )
 
     env.Append(LIBS=['rt', 'dl', 'pthread'],
@@ skipping 1261 matching lines @@
   nacl_env.ValidateSdk()
 
 if BROKEN_TEST_COUNT > 0:
   msg = "There are %d broken tests." % BROKEN_TEST_COUNT
   if GetOption('brief_comstr'):
     msg += " Add --verbose to the command line for more information."
   print msg
 
 # separate warnings from actual build output
 Banner('B U I L D - O U T P U T:')