serve: allow --daemon-postexec to be 'unlink:path' or 'none' This patch changes the format of value of --daemon-postexec. Now it can be either to unlink a file, or a no-op. The following patch will make chg to use the no-op option.

serve: rename --daemon-pipefds to --daemon-postexec (BC) Initially we use --daemon-pipefds to pass file descriptors for synchronization. Later, in order to support Windows, --daemon-pipefds is changed to accept a file path to unlink instead. The name is outdated since then. chg client is designed to use flock, which will be held before starting a server and until the client actually connects to the server it started. The unlink synchronization approach is not so helpful in this case. To address the issues, this patch renames pipefds to postexec and the following patch will allow the value of --daemon-postexec to be things like 'unlink:/path/to/file' or 'none'.

largefiles: don't explicitly list optional parameters that are not used This makes it easier for changes to the API.