Corrected an error when merging nodes during "ext2spice". The code

was checking for device terminals that were pointing to the
deallocated node and updating them.  However, it failed to check
for whether or not the substrate terminal was pointing to the
deallocated node, potentially causing a crash condition.  That has
now been fixed.

extflat/EFbuild.c

@@ -706,6 +706,11 @@ efBuildEquiv(def, nodeName1, nodeName2, resist, isspice)
 			dev->dev_terms[n].dterm_node =
 				(nn1->efnn_node == NULL) ?
 				nn2->efnn_node : nn1->efnn_node;
+
+		/* Also check the substrate terminal */
+		if (dev->dev_subsnode == lostnode)
+		    dev->dev_subsnode = (nn1->efnn_node == NULL) ?
+				nn2->efnn_node : nn1->efnn_node;
 	    }
 
 	    /* If a node has been merged away, make sure that its name	*/