diff --git a/ext/common/RandomGenerator.h b/ext/common/RandomGenerator.h
index 4a72a5e..836bf66 100644
--- a/ext/common/RandomGenerator.h
+++ b/ext/common/RandomGenerator.h
@@ -26,6 +26,7 @@
 #define _PASSENGER_RANDOM_GENERATOR_H_
 
 #include <string>
+#include <cerrno>
 
 #include <boost/noncopyable.hpp>
 #include <boost/shared_ptr.hpp>