diff -ur SOGo-5.1.1-old/GNUmakefile SOGo-5.1.1-new/GNUmakefile
--- SOGo-5.1.1-old/GNUmakefile	2021-06-02 09:06:14.000000000 -0500
+++ SOGo-5.1.1-new/GNUmakefile	2021-08-18 21:10:49.127002801 -0500
@@ -11,6 +11,7 @@
 	UI		\
 	Tools		\
 	Tests/Unit	\
+	ActiveSync	\
 
 
 include $(GNUSTEP_MAKEFILES)/aggregate.make