Wed Aug  9 17:54:30 UTC 2006  Alberto Bertogli <albertito@gmail.com>
  * Handle empty lines in print_darcs_diff().
  A "setpref" patch can output empty lines when seen with darcs_diff. Handle
  that case by ignoring them.
  
  Thanks to VMiklos from reporting it.
diff -rN -u old-darcsweb/darcsweb.cgi new-darcsweb/darcsweb.cgi
--- old-darcsweb/darcsweb.cgi	2015-11-15 13:04:01.000000000 +0000
+++ new-darcsweb/darcsweb.cgi	2015-11-15 13:04:01.000000000 +0000
@@ -1047,6 +1047,8 @@
 			continue
 
 		l = l.strip()
+		if not l:
+			continue
 
 		if l[0] == '+':
 			cl = 'class="pre" style="color:#008800;"'