Complete the backport of ALLOW_MISSING

Author: encukou

Lib/posixpath.py

@@ -438,7 +438,7 @@ def _joinrealpath(path, rest, strict, seen):
         newpath = join(path, name)
         try:
             st = os.lstat(newpath)
-        except OSError:
+        except ignored_error:
             is_link = False
         else:
             is_link = stat.S_ISLNK(st.st_mode)