Add config param 'index-info'

This parameter will be used to include a html file in the upcoming sidebar
on the index page.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
diff --git a/cgit.h b/cgit.h
index dd83f70..b8af970 100644
--- a/cgit.h
+++ b/cgit.h
@@ -124,6 +124,7 @@
 extern char *cgit_css;
 extern char *cgit_logo;
 extern char *cgit_index_header;
+extern char *cgit_index_info;
 extern char *cgit_logo_link;
 extern char *cgit_module_link;
 extern char *cgit_agefile;