diff --git a/Source/cmSystemTools.cxx b/Source/cmSystemTools.cxx
index a961d9245..321c4b484 100644
--- a/Source/cmSystemTools.cxx
+++ b/Source/cmSystemTools.cxx
@@ -1361,6 +1361,7 @@ bool cmSystemTools::IsPathToFramework(const char* path)
 
 #include <libtar/libtar.h>
 #include <memory> // auto_ptr
+#include <fcntl.h>
 
 bool cmSystemTools::CreateTar(const char* outFileName, const std::vector<cmStdString>& files)
 {