Add features flag to gmerge.

builder.py

 #!/usr/bin/python
 
 # Copyright (c) 2009-2011 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Package builder for the dev server."""
 import os
 import subprocess
 import sys
@@ skipping 33 matching lines @@
     return pkg in _OutputOf([
         'cros_workon', '--board=' + board, 'list', '--all'])
 
   def SetError(self, text):
     cherrypy.response.status = 500
     cherrypy.log(text, 'BUILD')
     return text
 
   def Build(self, board, pkg, additional_args):
     """Handles a build request from the cherrypy server."""
-    cherrypy.log('Additional build request arguments: '+ str(additional_args),
+    cherrypy.log('Additional build request arguments: ' + str(additional_args),
                  'BUILD')
 
-    original_use = os.environ.get('USE', '')
+    def _AppendStrToEnvVar(env, var, additional_string):
+      env[var] = env.get(var, '') + ' ' + additional_string
+      cherrypy.log('%s flags modified to %s' % (var, env[var]), 'BUILD')
+
+    env_copy = os.environ.copy()
     if 'use' in additional_args:
-      os.environ['USE'] = original_use + ' ' + additional_args['use']
-      cherrypy.log('USE flags modified to ' + os.environ['USE'], 'BUILD')
+      _AppendStrToEnvVar(env_copy, 'USE', additional_args['use'])
+
+    if 'features' in additional_args:
+      _AppendStrToEnvVar(env_copy, 'FEATURES', additional_args['features'])
 
     try:
       if (self._ShouldBeWorkedOn(board, pkg) and
           not additional_args.get('accept_stable')):
         return self.SetError(
             'Package is not cros_workon\'d on the devserver machine.\n'
             'Either start working on the package or pass --accept_stable '
             'to gmerge')
 
-      rc = subprocess.call(['emerge-%s' % board, pkg])
+      rc = subprocess.call(['emerge-%s' % board, pkg], env=env_copy)
       if rc != 0:
         return self.SetError('Could not emerge ' + pkg)
 
       cherrypy.log('ecleaning %s' % pkg, 'BUILD')
       rc = subprocess.call(['eclean-' + board, '-d', 'packages'])
       if rc != 0:
         return self.SetError('eclean failed')
 
       cherrypy.log('eclean complete %s' % pkg, 'BUILD')
       return 'Success\n'
     except OSError, e:
       return self.SetError('Could not execute build command: ' + str(e))
-    finally:
-      os.environ['USE'] =  original_use