[compat] Add functools.cached_property

yt_dlp/downloader/external.py

@@ -5,6 +5,7 @@ import sys
 import time
 
 from .fragment import FragmentFD
+from ..compat import functools
 from ..compat import compat_setenv, compat_str
 from ..postprocessor.ffmpeg import EXT_TO_OUT_FORMATS, FFmpegPostProcessor
 from ..utils import (
@@ -74,7 +75,7 @@ class ExternalFD(FragmentFD):
     def EXE_NAME(cls):
         return cls.get_basename()
 
-    @property
+    @functools.cached_property
     def exe(self):
         return self.EXE_NAME