fix `raco make -j'

Closes PR 12491

Merge to 5.2.1
(cherry picked from commit 350d0b1edf)

collects/setup/parallel-build.rkt

@@ -198,7 +198,7 @@
           [(cons hd tail)
               (define-values (dir file b) (split-path hd))
               (set! filelist tail)
-              (values hd (list (->bytes hd) (->bytes dir) (->bytes file)))]
+              (values hd (list (->bytes hd) (->bytes dir) (->bytes file) null))]
           [(list) null]))
       (define/public (has-jobs?) (not (null? filelist)))
       (define/public (jobs-cnt) (length filelist))

collects/tests/racket/parallel-build.rkt

@@ -0,0 +1,32 @@
+#lang racket
+(require setup/parallel-build)
+
+(define tmp1 (make-temporary-file))
+(define tmp2 (make-temporary-file))
+
+(define (mk file)
+  (with-output-to-file file 
+    #:exists 'truncate
+    (lambda ()
+      (printf "#lang racket/base\n"))))
+
+(mk tmp1)
+(mk tmp2)
+
+(parallel-compile-files 
+ (list tmp1 tmp2)
+ #:worker-count 2
+ #:handler (lambda (type work msg out err)
+             (match type
+               ['done (printf " Made ~a\n" work)]
+               ['output (printf " Output from: ~a\n~a~a" work out err)]
+               [else (eprintf " Error compiling ~a\n~a\n~a~a" work msg out err)])))
+
+(define (delete-files f)
+  (delete-file f)
+  (let-values ([(base name dir?) (split-path f)])
+    (delete-file (build-path base "compiled" (path-add-suffix name #".dep")))
+    (delete-file (build-path base "compiled" (path-add-suffix name #".zo")))))
+
+(delete-files tmp1)
+(delete-files tmp2)