pyside2 compile NameError: name "fcntl" is not defined

Traceback (most recent call last):
  File "setup.py", line 1266, in <module>
    ext_package = 'PySide2',
  File "G:\Python35\lib\distutils\core.py", line 148, in setup
    dist.run_commands()
  File "G:\Python35\lib\distutils\dist.py", line 955, in run_commands
    self.run_command(cmd)
  File "G:\Python35\lib\distutils\dist.py", line 974, in run_command
    cmd_obj.run()
  File "setup.py", line 702, in run
    self.build_extension(ext)
  File "setup.py", line 841, in build_extension
    if run_process(cmd_make) != 0:
  File "G:\PySide\pyside2-5.6\utils.py", line 380, in run_process
    log_buffer = _log(proc.read_async(wait=0.1, e=0))
  File "G:\PySide\pyside2-5.6\popenasync.py", line 112, in read_async
    r = pr()
  File "G:\PySide\pyside2-5.6\popenasync.py", line 94, in recv
    return self._recv('stdout', maxsize)
  File "G:\PySide\pyside2-5.6\popenasync.py", line 185, in _recv
    return self._close(which)
  File "G:\PySide\pyside2-5.6\popenasync.py", line 140, in _close
    flags = fcntl.fcntl(conn, fcntl.F_GETFL)
NameError: name 'fcntl' is not defined