diff --git a/racket/collects/setup/unixstyle-install.rkt b/racket/collects/setup/unixstyle-install.rkt
index 62e2f8195e..7205a34e99 100644
--- a/racket/collects/setup/unixstyle-install.rkt
+++ b/racket/collects/setup/unixstyle-install.rkt
@@ -368,27 +368,29 @@
        (define old (or (and (file-exists? src)
                             (call-with-input-file src read))
                        (hash)))
-       (define (preserve key)
-         (define val (hash-ref old key #f))
-         (when val
-           (printf "      (~s . ~s)\n" key val)))
        (with-output-to-file src #:exists 'truncate/replace
          (lambda ()
-           (printf ";; automatically generated by unixstyle-install\n")
-           (printf "#hash(")
-           (printf "(doc-dir . ~s)\n" (dir: 'doc))
-           (preserve 'catalogs)
-           (preserve 'doc-search-url)
-           (preserve 'build-stamp)
+           (define handled (make-hash))
+           (define (out! key val)
+             (printf "      (~a . ~s)\n" key val)
+             (hash-set! handled key #t))
+           (printf ";; generated by unixstyle-install\n")
+           (printf "#hash(\n")
+           (out! 'doc-dir (dir: 'doc))
            (when (eq? 'shared (system-type 'link)) ; never true for now
-             (printf "      (dll-dir . ~s)\n" (dir: 'lib)))
-           (printf "      (lib-dir . ~s)\n" (dir: 'librkt))
-           (printf "      (share-dir . ~s)\n" (dir: 'sharerkt))
-           (printf "      (include-dir . ~s)\n" (dir: 'includerkt))
-           (printf "      (bin-dir . ~s)\n" (dir: 'bin))
-           (printf "      (apps-dir . ~s)\n" (dir: 'apps))
-           (printf "      (man-dir . ~s)\n" (dir: 'man))
-           (printf "      (absolute-installation? . #t))\n"))))]))
+             (out! 'dll-dir (dir: 'lib)))
+           (out! 'lib-dir (dir: 'librkt))
+           (out! 'share-dir (dir: 'sharerkt))
+           (out! 'include-dir (dir: 'includerkt))
+           (out! 'bin-dir (dir: 'bin))
+           (out! 'apps-dir (dir: 'apps))
+           (out! 'man-dir (dir: 'man))
+           (out! 'absolute-installation? #t)
+           ;; Preserve all other keys:
+           (for ([(key val) (in-hash old)])
+             (unless (hash-ref handled key #f)
+               (out! key val)))
+           (printf ")\n"))))]))
 
 ;; creates a directory including its ancestors when needed
 (define (make-dir* dir)