--- qTox-1.8.1/src/persistence/db/rawdatabase.h
+++ qTox-1.8.1/src/persistence/db/rawdatabase.h
@@ -11,6 +11,7 @@
 #include <QVariant>
 #include <memory>
 #include <atomic>
+#include <functional>
 
 struct sqlite3;
 struct sqlite3_stmt;