diff --git a/platform.cpp b/platform.cpp
index e986fd943b..3b53108bc0 100644
--- a/platform.cpp
+++ b/platform.cpp
@@ -39,6 +39,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 #include <QX11Info>
 
+#include <cerrno>
+
 namespace KWin
 {