gitk: Recognize -L option

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>

gitk

@@ -235,6 +235,14 @@ proc parseviewargs {n arglist} {
 		set filtered 1
 		lappend glflags $arg
 	    }
+	    "-L*" {
+		# Line-log with 'stuck' argument (unstuck form is
+		# not supported)
+		set filtered 1
+		set vinlinediff($n) 1
+		set allknown 0
+		lappend glflags $arg
+	    }
 	    "-n" {
 		# This appears to be the only one that has a value as a
 		# separate word following it