Allow git-viz to display diffs without cogito
and thus make it work with hgit.
Index: git-viz-0.1/git.ml
===================================================================
--- git-viz-0.1.orig/git.ml	2005-06-17 09:07:54.000000000 +0200
+++ git-viz-0.1/git.ml	2005-06-20 00:50:12.136776776 +0200
@@ -326,10 +326,10 @@
 	cb (`SUB_PROC_ERROR "Diffs are not suported with git yet") ;
 	false))
   | `PASKY ->
-      let cmd = [ "cg-diff"; "-r"; parent^":"^child ] in
+      let cmd = [ "git-diff-tree"; "-r"; "-p"; parent; child ] in
       log "exec" "### exec: Running '%s'" (String.concat " " cmd) ;
       try
-	status#push "Running cg-diff ..." ;
+	status#push "Running git-diff-tree ..." ;
 	ignore (
 	Subprocess.spawn_out 
 	  ~working_directory:d.base
@@ -339,10 +339,10 @@
 	    if status <> 0 then
 	      if stderr = ""
 	      then 
-		error "cg-diff exited with status %d:\n%s" status 
+		error "git-diff-tree exited with status %d:\n%s" status 
 		  (String.concat "\n" (List.map Printexc.to_string exceptions))
 	      else 
-		error "cg-diff error:\n%s" stderr
+		error "git-diff-tree error:\n%s" stderr
 	    else
 	      cb (`DIFF stdout)))
       with Gspawn.Error (_, msg) ->