osutil._listdir: rename to _listdir_stat In upcoming patches we'll add another implementation of listdir on OS X. That implementation will have to fall back to this one under some circumstances, though. We'll make _listdir be able to detect those circumstances and use the right function as appropriate.

revset: optimize "x & fullreposet" case If self is a smartset and other is a fullreposet, nothing should be necessary. A small win for trivial query in mozilla-central repo: revset #0: (0:100000) 0) wall 0.017211 comb 0.020000 user 0.020000 sys 0.000000 (best of 163) 1) wall 0.001324 comb 0.000000 user 0.000000 sys 0.000000 (best of 2160)