diff --git a/src/lib/case_insensitive_sorter.cc b/src/lib/case_insensitive_sorter.cc
index 1dfdb01f3..c7cc8dadc 100644
--- a/src/lib/case_insensitive_sorter.cc
+++ b/src/lib/case_insensitive_sorter.cc
@@ -21,6 +21,7 @@
 #include "case_insensitive_sorter.h"
 #include <boost/filesystem.hpp>
 #include <boost/foreach.hpp>
+#include <algorithm>
 #include <iostream>
 
 using std::string;