listdir: add support for aborting if a certain path is found
This lets us bail out early if we find '.hg', letting us skip sorting
and bisecting for it.
osutil: fix some braindamage
- entkind returns -1 on failure
- compile if AT_SYMLINK_NOFOLLOW is missing
- avoid fullpath overflow
hgweb: let the web graph cope with low revisions/new repositories (
issue1293)
hgweb: Respond with HTTP 403 for disabled archive types instead of 404
This makes it easier for clients/users to distinct between supported
but disabled and unsupported archive types.