--- ./prog/checker_string.cpp.orig	2011-07-04 12:22:23.000000000 +0300
+++ ./prog/checker_string.cpp	2014-12-23 09:52:46.000000000 +0200
@@ -6,6 +6,7 @@
 
 #include <assert.h>
 
+#include <assert.h>
 #include "checker_string.hpp"
 #include "speller.hpp"
 #include "document_checker.hpp"