chgserver: add utilities to calculate confighash
confighash is the hash of sensitive config items like [extensions], and
sensitive environment variables like HG*, LD_*, etc. The config items
can come from global, user, repo config, and command line flags.
For chgserver, it is designed that once confighash changes, the server is
not qualified to serve its client and should redirect the client to a new
server. The server does not need to exit in this case, since it can still
be valid (have a matched confighash) to serve other chg clients.
Mercurial
=========
Mercurial is a fast, easy to use, distributed revision control tool
for software developers.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
Running without installing:
$ make local # build for inplace usage
$ ./hg --version # should show the latest version
See https://mercurial-scm.org/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.