Work around an issue with NaCl build with long path name.

masters/master.chromium.swarm/master.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 from buildbot.scheduler import Scheduler
 from buildbot.schedulers import timed
 from buildbot.status import mail
@@ skipping 56 matching lines @@
 # ----------------------------------------------------------------------------
 # BUILDER DEFINITIONS
 
 def RecipeBasedFactory(config):
   return annotator_factory.AnnotatorFactory().BaseFactory(
       'swarming/canary', factory_properties={'configuration': config})
 
 def DeterministicBuilderFactory(platform):
   return  {
       'name': '%s deterministic build' % platform,
+      # Work around an issue with NaCl build.
+      'slavebuilddir': 'chr',
       'factory': annotator_factory.AnnotatorFactory().BaseFactory(
           'swarming/deterministic_build',
           factory_properties = {
             'configuration': 'Release',
           }),
       'auto_reboot': False,
       'category': 'deterministic',
     }
 
 b_heartbeat = {
@@ skipping 133 matching lines @@
 #    sendToInterestedUsers=False,
 #    extraRecipients=[
 #      'chrome-troopers+swarming@google.com',
 #    ]))
 
 
 ####### PROJECT IDENTITY
 
 c['projectName'] = ActiveMaster.project_name
 c['projectURL'] = config.Master.project_url