diff --git a/src/qtsingleapp/qtlocalpeer.cpp b/src/qtsingleapp/qtlocalpeer.cpp
index e76735a95..72f8cd6db 100644
--- a/src/qtsingleapp/qtlocalpeer.cpp
+++ b/src/qtsingleapp/qtlocalpeer.cpp
@@ -58,7 +58,7 @@ static PProcessIdToSessionId pProcessIdToSessionId = 0;
 #if defined(Q_OS_UNIX)
 #include <time.h>
 #endif
-#if defined(Q_OS_OS2)
+#if defined(Q_OS_OS2) || defined(Q_OS_UNIX)
 #include <unistd.h>
 #endif