From
<http://git.pld-linux.org/gitweb.cgi/packages/perl-Event-Lib.git/commitdiff/d735f6ac4ae17f4dc1cfe16232ea605c9acb89d2>

--- Event-Lib-1.04/Lib.xs~	2014-09-23 09:06:55.000000000 +0200
+++ Event-Lib-1.04/Lib.xs	2017-04-04 19:35:35.623351764 +0200
@@ -128,7 +128,7 @@
 void refresh_event (struct event_args *args, char *class) {
     SV *sv = newSV(0);
     sv_setref_pv(sv, class, (void*)args);
-    args->ev.ev_arg = (void*)sv;
+    args->ev.ev_evcallback.evcb_arg = (void*)sv;
 }
 
 SV * do_exception_handler (pTHX_ short event, SV *ev, SV *err) {
@@ -208,7 +208,7 @@
      * handlers, in which case the ref-cnt has already been decremented */
     if (!event_pending(&args->ev, event, NULL)) {
 	EvEVENT_SET_off(args);
-    	SvREFCNT_dec((SV*)args->ev.ev_arg);
+    	SvREFCNT_dec((SV*)args->ev.ev_evcallback.evcb_arg);
 	if (SvOK(ev))
 	    DEBUG_trace(args);
     }
@@ -582,7 +582,7 @@
 	}
 	
 	/* Nope, it's another event so it's ok to increment the ref-cnt */
-	SvREFCNT_inc((SV*)args->ev.ev_arg);
+	SvREFCNT_inc((SV*)args->ev.ev_evcallback.evcb_arg);
 	DEBUG_record_event(aTHX_ ST(0));
 	DEBUG_trace(args);
 	XSRETURN(1);
@@ -689,7 +689,7 @@
 	    /* We are not using ST(0) here but instead the loop-back
 	     * object stored inside the event because this is what is
 	     * decremented in do_callback and incremented in event_add */
-	    SvREFCNT_dec((SV*)args->ev.ev_arg);
+	    SvREFCNT_dec((SV*)args->ev.ev_evcallback.evcb_arg);
 
 	DEBUG_trace(args);
     }