Reproduce crash where synthetic revs break merge detection (issue1578).
(The fix for this was committed as 9bbcfa898cd3.)
Slightly edited by Patrick Mezard <pmezard@gmail.com>
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.