symlinks: minimal support for symlinks in merge/update
This will get angry, confused, and sad if you try to merge a symlink
with a regular file.
Basic install:
$ make # see install targets
$ make install # do a system-wide install
$ hg debuginstall # sanity-check setup
$ hg # see help
See http://www.selenic.com/mercurial/ for detailed installation
instructions, platform-specific notes, and Mercurial user information.