diff --git a/simgear/structure/subsystem_mgr.cxx b/simgear/structure/subsystem_mgr.cxx
index b01a0ffe..eeda8663 100644
--- a/simgear/structure/subsystem_mgr.cxx
+++ b/simgear/structure/subsystem_mgr.cxx
@@ -22,6 +22,8 @@
 #  include <simgear_config.h>
 #endif
 
+#include <algorithm>
+
 #include <simgear/debug/logstream.hxx>
 #include <simgear/timing/timestamp.hxx>