bug#47064: DrRacket internal error uncompressing

[Jack Hill]

Hi Guix,

Using guix 80739ea480a7db667b83b45e3a08be740449f689 on x86_64, running:

`guix environment --ad-hoc racket -- drracket` produces:

```
$bytevector-uncompress: internal error uncompressing 
#"\0\0\0\0chez\310\224\206:\r()#\201\256R-d\205\233\24\363\5\20\201P\6A\v\300\0\16\f\6\31\2\f\6\f&H\275\0\1\0\362\bA\377e\0\1\0C\6A\21\3\v\300\0\201\265!\f\6\n\0\a\1\35\0\1+\0\360\27\201\375\300\0\0\0\17\205\210Z\0\0M\215\245\b\4\0\0M9fH\17\206fZ\0\0I\2...
  context...:
   body of 
"/gnu/store/mmrax3f1vx3c8ih9hhgffpvka6chk96w-racket-8.0/share/racket/pkgs/gui-lib/mred/private/wx/gtk/utils.rkt"
   body of 
"/gnu/store/mmrax3f1vx3c8ih9hhgffpvka6chk96w-racket-8.0/share/racket/pkgs/gui-lib/mred/private/wx/platform.rkt"
```

However, `guix time-machine --commit=b1248016e0492e1897f4d1127ccb07736c9bb6a5 
-- environment --ad-hoc racket -- drracket`

successfully opens drracket. b1248016e0492e1897f4d1127ccb07736c9bb6a5 is 
the commit before the Racket 8.0 update, so I think the update introduced 
the problem. Other Racket GUI programs like slideshow and gracket also 
also exhibit the problem. The command line REPL works however.

I have not investigated to determine if the problem is specific to the GUI 
packages or if loading other extra Racket packages would also exhibit the 
problem.

Best,
Jack