convert/svn: better error when hg cannot call itself (
issue1838)
patch: handle symlink updates/replacements (
issue1785)
patch: handle symlinks without symlinkhunk
Symlink creations and deletions were handled with a special symlinkhunk object,
working like a binary hunk. However, this model does not support symlink
updates or replacements, so we teach regular hunks how to handle symlinks.
bisect: use util.system and fix good/bad when using -c
The existing scheme using util.find_exe and subprocess.call meant we
couldn't use simple shell commands in tests. Fix that.
Also, it mistakenly used status from the system() call rather than
good from the bisect call in reporting results.