--- a/widget/gtk/WakeLockListener.cpp
+++ b/widget/gtk/WakeLockListener.cpp
@@ -10,6 +10,7 @@
 #include "WakeLockListener.h"
 #include "WidgetUtilsGtk.h"
 #include "mozilla/ScopeExit.h"
+#include "prenv.h"
 
 #ifdef MOZ_ENABLE_DBUS
 #  include <gio/gio.h>