--- ./src/lib/libast/misc/stk.c.orig	2014-11-22 10:46:29.708285640 +0000
+++ ./src/lib/libast/misc/stk.c	2014-11-22 10:48:32.533777385 +0000
@@ -378,6 +378,8 @@ char *stkset(register Sfio_t * stream, r
 		frames++;
 	}
 	/* set stack back to the beginning */
+	if (loc)
+		abort();
 	cp = (char*)(fp+1);
 	if(frames)
 		sfsetbuf(stream,cp,sp->stkend-cp);