diff --git a/src/kernel/qlock.cpp b/src/kernel/qlock.cpp
index f8b8be46..948e7602 100644
--- a/src/kernel/qlock.cpp
+++ b/src/kernel/qlock.cpp
@@ -47,6 +47,7 @@
 #include <sys/stat.h>
 #include <sys/file.h>
 #else
+#define _WANT_SEMUN
 #include <sys/sem.h>
 #if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED) \
     || defined(Q_OS_FREEBSD) || defined(Q_OS_OPENBSD) || defined(Q_OS_NETBSD) || defined(Q_OS_BSDI)