bug#57309: 29.0.50; Build error "trying to dump non fixed-up eln file"

["Gerd Möllmann" <gerd.moellmann@gmail.com>]

(lldb) p globals.f_Vcomp_loaded_comp_units_h 
(Lisp_Object) $176 = 0x00000001040382b5 (struct Lisp_Hash_Table *) $181 = 0x00000001040382b0
(lldb) p *$181
(struct Lisp_Hash_Table) $182 = {
  header = (size = 4611686018662313988)
  weak = 0x000000000000fdb0 (struct Lisp_Symbol *) $185 = 0x00000001007d2b90
  hash = 0x00000001042d10b5 (struct Lisp_Vector *) $189 = 0x00000001042d10b0
  next = 0x00000001042d078d (struct Lisp_Vector *) $193 = 0x00000001042d0788
  index = 0x00000001042d1605 (struct Lisp_Vector *) $197 = 0x00000001042d1600
  count = 90
  next_free = 90
  purecopy = false
  mutable = true
  rehash_threshold = 0.8125
  rehash_size = 0.5
  key_and_value = 0x00000001042d0a9d (struct Lisp_Vector *) $201 = 0x00000001042d0a98
  test = {
    name = 0x00000000000060c0 (struct Lisp_Symbol *) $204 = 0x00000001007c8ea0
    user_hash_function = NULL
    user_cmp_function = NULL
    cmpfn = 0x000000010017ed70 (temacs`cmpfn_equal at fns.c:4235)
    hashfn = 0x000000010017ed9c (temacs`hashfn_equal at fns.c:4266)
  }
  next_weak = NULL
}
(lldb) xdebug_print $176
...lots of output...
 "/Users/gerd/emacs/master/native-lisp/29_0_50-2dce7c3a/preloaded/window-0d1b8b93-274db3e2.eln" #<native compilation unit: /Users/gerd/emacs/master/native-lisp/29_0_50-2dce7c3a/preloaded/window-0d1b8b93-274db3e2.eln ((native-comp-speed . 2) (native-comp-debug . 0) (gccjit 12 1 0))>
...

I'm not 100% sure, but I interpret that as meaning that the window.eln
in question has already been loaded before, and the second attempt then
fails.  Unless I misread the code of course, which is always possible.

But how that might happen escapes me ATM.