Introduce find_exe. Use instead of find_in_path for programs. The behaviour of find_in_path was broken for config options containing path names, because it always searched the given path, even when not necessary. The find_exe function is more polite: if the name passed to it contains a path component, it just returns it.

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.