destroy the tmalloced diag, if rshunt option was enabled

src/spicelib/analysis/cktdest.c

@@ -18,6 +18,7 @@ Author: 1985 Thomas L. Quarles
 #ifdef XSPICE
 #include "ngspice/evtproto.h"
 #include "ngspice/mif.h"
+#include "ngspice/enh.h"
 #endif
 
 int
@@ -88,6 +89,8 @@ CKTdestroy(CKTcircuit *ckt)
 
 #ifdef XSPICE
     EVTdest(ckt->evt);
+    if (ckt->enh->rshunt_data.enabled)
+        FREE(ckt->enh->rshunt_data.diag);
     FREE(ckt->enh);
     FREE(ckt->evt);
 #endif