Use git ls-tree to collect source files instead of walking the fs

tools/oom_dump/SConstruct

-# Copyright 2010 the V8 project authors. All rights reserved.
-# Redistribution and use in source and binary forms, with or without
-# modification, are permitted provided that the following conditions are
-# met:
-#
-#     * Redistributions of source code must retain the above copyright
-#       notice, this list of conditions and the following disclaimer.
-#     * Redistributions in binary form must reproduce the above
-#       copyright notice, this list of conditions and the following
-#       disclaimer in the documentation and/or other materials provided
-#       with the distribution.
-#     * Neither the name of Google Inc. nor the names of its
-#       contributors may be used to endorse or promote products derived
-#       from this software without specific prior written permission.
-#
-# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-vars = Variables('custom.py')
-vars.Add(PathVariable('BREAKPAD_DIR',
-                      'Path to checkout of google-breakpad project',
-                      '~/google-breakpad',
-                      PathVariable.PathIsDir))
-vars.Add(PathVariable('V8_DIR',
-                      'Path to checkout of v8 project',
-                      '../..',
-                      PathVariable.PathIsDir))
-
-env = Environment(variables = vars,
-                  CPPPATH = ['${BREAKPAD_DIR}/src', '${V8_DIR}/src'],
-                  LIBPATH = ['/usr/local/lib', '${V8_DIR}'])
-
-env.Program('oom_dump.cc', LIBS = ['breakpad', 'v8', 'pthread'])