This gives line-log support to gitk, by exploiting the new support for
processing and showing "inline" diffs straight from the git-log
output.

Note that we 'set allknown 0', which is a bit counterintuitive since
this is a "known" option.  But that flag prevents gitk from thinking
it can optimize the view by running rev-list to see the topology; in
the -L case that doesn't work.
Signed-off-by: NThomas Rast <trast@inf.ethz.ch>
Signed-off-by: NPaul Mackerras <paulus@samba.org>