102             _set.add(_globals[fn])
104     _set = set()  variable
121     supports_dir_fd = _set
123     _set = set()  variable
125     supports_effective_ids = _set
127     _set = set()  variable
134     _set.add(stat) # fstat always works
141     supports_fd = _set
143     _set = set()  variable
178     supports_follow_symlinks = _set
180     del _set