File harmonySEQ-atomic.patch of Package harmonyseq

diff -up harmonySEQ-0.17/src/Engine.hpp.orig harmonySEQ-0.17/src/Engine.hpp
--- harmonySEQ-0.17/src/Engine.hpp.orig	2020-03-04 14:48:23.000000000 +0100
+++ harmonySEQ-0.17/src/Engine.hpp	2020-09-27 09:21:43.731220834 +0200
@@ -22,6 +22,7 @@
 #ifndef MIDIDRIVER_H
 #define	MIDIDRIVER_H
 
+#include <atomic>
 #include <boost/signals2.hpp>
 namespace bs2 = boost::signals2;