bug#57593: Racket 8.6 is not reproducible

[Ludovic Courtès]

Hey,

Just noticed that Racket does not build in a reproducible fashion:

--8<---------------cut here---------------start------------->8---
$ guix describe
Generation 227  Sep 04 2022 23:39:52    (current)
  guix aae98c2
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: aae98c297214f87eb45302863adb021078c41a6f
$ guix challenge racket | head -40
/gnu/store/av255rh362283i1zaiq9rz4rpli69j59-racket-8.6 contents differ:
  local hash: 1w4dnkvpbbrgfasyq8x1cbqw58jzqsny17ms5l1fb1h6iid38bs1
  https://ci.guix.gnu.org/nar/lzip/av255rh362283i1zaiq9rz4rpli69j59-racket-8.6: 
1lnxklizpnc599w7n2svb1jaw595wranm9aagd2928fcbiaavbr6
  differing files:
    /lib/racket/pkgs/2d-doc/scribblings/compiled/2d_scrbl.dep
    /lib/racket/pkgs/2d-doc/scribblings/compiled/2d_scrbl.zo
    /lib/racket/pkgs/algol60/compiled/algol60_rkt.dep
    /lib/racket/pkgs/algol60/compiled/algol60_scrbl.dep
    /lib/racket/pkgs/algol60/compiled/algol60_scrbl.zo
    /lib/racket/pkgs/algol60/compiled/cfg-parser_rkt.dep
    /lib/racket/pkgs/algol60/compiled/compile_rkt.dep
    /lib/racket/pkgs/algol60/compiled/parse_rkt.dep
    /lib/racket/pkgs/algol60/compiled/parse_rkt.zo
    /lib/racket/pkgs/algol60/compiled/simplify_rkt.dep
    /lib/racket/pkgs/algol60/compiled/tool_rkt.dep
    /lib/racket/pkgs/algol60/lang/compiled/reader_rkt.dep
    /lib/racket/pkgs/algol60/tests/compiled/export_rkt.dep
    /lib/racket/pkgs/algol60/tests/compiled/export_rkt.zo
    /lib/racket/pkgs/algol60/tests/compiled/syncheck-test_rkt.dep
    /lib/racket/pkgs/algol60/tests/compiled/test_rkt.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/awk_scrbl.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/awk_scrbl.zo
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/cmdline_scrbl.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/cmdline_scrbl.zo
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/cml_scrbl.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/cml_scrbl.zo
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/common_rkt.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/common_rkt.zo
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/compat_scrbl.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/compat_scrbl.zo
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/compile_scrbl.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/compile_scrbl.zo
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/contract-label_rkt.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/contract_scrbl.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/contract_scrbl.zo
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/etc_scrbl.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/etc_scrbl.zo
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/file_scrbl.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/file_scrbl.zo
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/for_scrbl.dep
    /lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/for_scrbl.zo
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/include_scrbl.dep
    
/lib/racket/pkgs/compatibility-doc/mzlib/scribblings/compiled/include_scrbl.zo
--8<---------------cut here---------------end--------------->8---

Ludo’.