ofSingleton lock_guard fix (#8129)

dimitre · web-flow · commit d9c11b9c1646 · 2024-10-07T23:47:48.000-03:00
diff --git a/libs/openFrameworks/utils/ofSingleton.h b/libs/openFrameworks/utils/ofSingleton.h
@@ -8,6 +8,7 @@
 #include <cassert>
 #include <shared_mutex>
 #include <utility>
+#include <mutex>
 
 namespace of::utils {
 
