Developed in-house but accepted upstream.

--- tcsh-6.18.01/sh.sem.c.orig	Sat Oct 31 10:58:21 2015
+++ tcsh-6.18.01/sh.sem.c	Sat Oct 31 10:59:42 2015
@@ -212,8 +212,14 @@
 	 * If noexec then this is all we do.
 	 */
 	if (t->t_dflg & F_READ) {
+	    int	old_pintr_disabled;
+	    
 	    xclose(0);
+	    if (setintr)
+	        pintr_push_enable(&old_pintr_disabled);
 	    heredoc(t->t_dlef);
+	    if (setintr)
+	        cleanup_until(&old_pintr_disabled);
 	    if (noexec)
 		xclose(0);
 	}