Keep only base/extractor.[cc|h].

tools/build.scons

-# Copyright 2008-2009 Google Inc.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#      http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-# ========================================================================
-
-Import('env')
-
-subdirs = []
-
-if not env.Bit('min'):
-  subdirs += [
-      'ApplyTag',
-      'CrashProcess',
-      ]
-
-for dir in subdirs:
-  env.BuildSConscript(dir)