Really revert BACKGROUND-YIELD to CAUSEINTERRUPT until Maiko fixed (#2397)

I'm not sure what I did wrong with PR #2396 but it didn't revert
lispusers/BACKGROUND-YIELD(.LCOM).

I did what I thought was the same process, but it seems to have picked
up the right files this time.

Author: MattHeffron

lispusers/BACKGROUND-YIELD

@@ -1,12 +1,12 @@
 (DEFINE-FILE-INFO PACKAGE "INTERLISP" READTABLE "INTERLISP" BASE 10)
 
-
(FILECREATED " 9-Nov-2025 11:52:07" {DSK}<Users>larry>il>MEDLEY>LISPUSERS>BACKGROUND-YIELD.;2
 1882   
+
(FILECREATED "28-Jul-2023 09:49:24" {DSK}<home>larry>il>medley>lispusers>BACKGROUND-YIELD.;2
 1770   
 
       :EDIT-BY "lmm"
 
       :CHANGES-TO (FNS BACKGROUND-YIELD)
 
-      :PREVIOUS-DATE "28-Jul-2023 09:49:24" {DSK}<Users>larry>il>MEDLEY>LISPUSERS>BACKGROUND-YIELD.;1
+      :PREVIOUS-DATE "14-Nov-2021 22:05:58" {DSK}<home>larry>il>medley>lispusers>BACKGROUND-YIELD.;1
 )
 
 
@@ -26,14 +26,13 @@
 (DEFINEQ
 
 (BACKGROUND-YIELD

-  [LAMBDA NIL
                                                (* ; "Edited  9-Nov-2025 11:50 by lmm")


-                                                             (* ; "Edited 28-Jul-2023 09:11 by lmm")


+  [LAMBDA NIL
                                                (* ; "Edited 28-Jul-2023 09:11 by lmm")


                                                            (* ; "Edited 20-Sep-2021 11:37 by larry")

     (LET ((\BACKGROUND T))
-         (DECLARE
 (SPECVARS \BACKGROUND)
-                (GLOBALVARS BACKGROUND-YIELD))
+         (DECLARE
 (SPECVARS \BACKGROUND))
          (IF
 (FIXP BACKGROUND-YIELD)
-             THEN
 (SUBRCALL YIELD BACKGROUND-YIELD])
+             THEN
 (SUBRCALL YIELD BACKGROUND-YIELD)
+                  (SUBRCALL CAUSE-INTERRUPT])
 
 (INIT-YIELD

   [LAMBDA (ONP)
                                        (* ; "Edited 19-Sep-2021 13:32 by larry")

@@ -52,5 +51,5 @@
 
 (RPAQQ BACKGROUND-YIELD
 833333)
 (DECLARE%: DONTCOPY
-  (FILEMAP (NIL (808 1767 (BACKGROUND-YIELD 818 . 1383) (INIT-YIELD 1385 . 1765)))))
+  (FILEMAP (NIL (806 1655 (BACKGROUND-YIELD 816 . 1271) (INIT-YIELD 1273 . 1653)))))
 STOP