diff -Naur drbd-utils-9.13.0.orig/user/v84/drbdadm.h drbd-utils-9.13.0/user/v84/drbdadm.h
--- drbd-utils-9.13.0.orig/user/v84/drbdadm.h	2020-06-08 16:00:20.166480137 +0800
+++ drbd-utils-9.13.0/user/v84/drbdadm.h	2020-06-08 16:00:42.930652069 +0800
@@ -251,7 +251,7 @@
 	bool explicit;
 	char *option;
 };
-struct setup_option *setup_options;
+extern struct setup_option *setup_options;
 
 extern void add_setup_option(bool explicit, char *option);