diff --git a/src/libs/clangbackendipc/connectionserver.h b/src/libs/clangbackendipc/connectionserver.h
index 4e3c0b18f33..53033bf9801 100644
--- a/src/libs/clangbackendipc/connectionserver.h
+++ b/src/libs/clangbackendipc/connectionserver.h
@@ -32,6 +32,7 @@
 #include <QLocalSocket>
 #include <QTimer>
 
+#include <cstdlib>
 #include <memory>
 #include <vector>