Cleanup pylint errors

pylib/gyp/mac_tool.py

 #!/usr/bin/env python
 # Copyright (c) 2012 Google Inc. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Utility functions to perform Xcode-style build steps.
 
 These functions are executed via gyp-mac-tool when using the Makefile generator.
 """
 
@@ skipping 128 matching lines @@
     fd.close()
 
     # Insert synthesized key/value pairs (e.g. BuildMachineOSBuild).
     plist = plistlib.readPlistFromString(lines)
     if keys:
       plist = dict(plist.items() + json.loads(keys[0]).items())
     lines = plistlib.writePlistToString(plist)
 
     # Go through all the environment variables and replace them as variables in
     # the file.
-    IDENT_RE = re.compile('[/\s]')
+    IDENT_RE = re.compile(r'[/\s]')
     for key in os.environ:
       if key.startswith('_'):
         continue
       evar = '${%s}' % key
       evalue = os.environ[key]
       lines = string.replace(lines, evar, evalue)
 
       # Xcode supports various suffices on environment variables, which are
       # all undocumented. :rfc1034identifier is used in the standard project
       # template these days, and :identifier was used earlier. They are used to
@@ skipping 418 matching lines @@
         data = data.replace('$(%s)' % key, value)
       return data
     if isinstance(data, list):
       return [self._ExpandVariables(v, substitutions) for v in data]
     if isinstance(data, dict):
       return {k: self._ExpandVariables(data[k], substitutions) for k in data}
     return data
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))