https://github.com/NixOS/nixpkgs/issues/114993

racket-cs-nixos-problem.rkt

#lang racket/base
(require setup/dirs
         setup/variant
         setup/cross-system
         racket/promise)

(define plain-variant
  (delay/sync
   (cond
    [(cross-installation?)
     (if (eq? 'chez-scheme (cross-system-type 'vm))
         'cs
         (cross-system-type 'gc))]
    [else
     (let* ([dir (find-console-bin-dir)]
            [exe (cond [(eq? 'windows (system-type)) "Racket.exe"]
                       [(equal? #".dll" (system-type 'so-suffix))
                        ;; in cygwin so-suffix is ".dll"
                        "racket.exe"]
                       [else "racket"])]
            [f (build-path dir exe)])
       (displayln (list 'plain-variant 'f f))
       (and (file-exists? f)
            (with-input-from-file f
              (lambda ()
                (define m (regexp-match #rx#"bINARy tYPe:..(.)"
                                        (current-input-port)))
                (cond
                 [(not m) '3m]
                 [(equal? (cadr m) #"c") 'cgc]
                 [(equal? (cadr m) #"s") 'cs]
                 [else '3m])))))])))

(define (find-exe #:cross? [cross? #f]
                  #:untethered? [untethered? #f]
                  [mred? #f]
                  [variant (if cross?
                               (cross-system-type 'gc)
                               (system-type 'gc))])
  (let* ([base (if mred?
                   (or (and (not untethered?)
                            (find-addon-tethered-gui-bin-dir)
                            (find-config-tethered-gui-bin-dir))
                       (find-lib-dir))
                   (or (and (not untethered?)
                            (find-addon-tethered-console-bin-dir)
                            (find-config-tethered-console-bin-dir))
                       (find-console-bin-dir)))]
         [fail
          (lambda ()
            (error 'find-exe
                   "can't find ~a executable for variant ~a"
                   (if mred? "GRacket" "Racket")
                   variant))])
    (let ([exe (build-path
                base
                (case (if cross?
                          (cross-system-type)
                          (system-type))
                  [(macosx)
                   (cond
                    [(not mred?)
                     ;; Need Racket:
                     (string-append "racket" (variant-suffix variant #f))]
                    [mred?
                     ;; Need GRacket:
                     (let ([sfx (variant-suffix variant #t)])
                       (build-path (format "GRacket~a.app" sfx)
                                   "Contents" "MacOS"
                                   (format "GRacket~a" sfx)))])]
                  [(windows)
                   (format "~a~a.exe" (if mred?
                                          "GRacket"
                                          "Racket")
                           (variant-suffix variant #t))]
                  [(unix)
                   (format "~a~a" (if mred?
                                      "gracket"
                                      "racket")
                           (variant-suffix variant #f))]))])
      (displayln (list 'find-exe
                       'exe exe
                       '(cross-system-type) (cross-system-type)
                       'mred? mred?
                       'variant variant
                       '(get-cs-suffix) (get-cs-suffix)
                       '(force plain-variant) (force plain-variant)
                       '(cross-installation?) (cross-installation?)
                       '(variant-suffix variant #f) (variant-suffix variant #f)))
      (unless (or (file-exists? exe)
                  (directory-exists? exe))
        (fail))
      exe)))

(find-exe)