code: def _get_platlib_dir(cmd):
      
  
      plat_specifier = '.{0}-{1}'.format(cmd.plat_name, sys.version[0:3])
      return os.path.join(cmd.build_base, 'lib' + plat_specifier)
docs: Given a build command, return the name of the appropriate platform-specific
      build subdirectory directory (e.g. build/lib.linux-x86_64-2.7)