diff --git a/src/fetcher.h b/src/fetcher.h
index 0a0fe9d..185e2a1 100644
--- a/src/fetcher.h
+++ b/src/fetcher.h
@@ -29,6 +29,8 @@
 #include <boost/intrusive/list.hpp>
 #include <boost/date_time/posix_time/posix_time_types.hpp>
 
+#include <set>
+
 class FetchManager;
 
 class Fetcher