--- tcsh-6.22.02/sh.h
+++ tcsh-6.22.02/sh.h	2020-01-08 12:05:37.346589832 +0000
@@ -566,7 +566,7 @@ EXTERN int    neednote IZERO;	/* Need to
 EXTERN int    noexec IZERO;	/* Don't execute, just syntax check */
 EXTERN int    pjobs IZERO;	/* want to print jobs if interrupted */
 EXTERN int    setintr IZERO;	/* Set interrupts on/off -> Wait intr... */
-EXTERN int    handle_interrupt IZERO;/* Are we currently handling an interrupt? */
+extern int    handle_interrupt IZERO;/* Are we currently handling an interrupt? */
 EXTERN int    havhash IZERO;	/* path hashing is available */
 EXTERN int    editing IZERO;	/* doing filename expansion and line editing */
 EXTERN int    noediting IZERO;	/* initial $term defaulted to noedit */