bug#24028: Linux-libre kernel does not build deterministically

[Ludovic Courtès]

As of version 4.6.4, Linux-libre does not build reproducibly:

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$ guix challenge linux-libre
/gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4 contents differ:
  local hash: 1py214sd42qcq8l429m4zf4aibp8rl68kpkrzqi1nn65vnbxsx11
  https://hydra.gnu.org/nar/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4: 
19hsdsjy5i9nfc1g28s074znzimzhylgkdpwz435j301sn9pxxp9
$ wget -q -O - 
https://hydra.gnu.org/nar/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4 | 
bunzip2 | guix archive -x t
$ diff -ur --no-dereference 
/gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4 /tmp/t
Binary files 
/gnu/store/wkdnd1dcgljr0jxmd3li8j0qsr2zwrci-linux-libre-4.6.4/bzImage and 
/tmp/t/bzImage differ
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Apparently people are working on it:
<https://wiki.debian.org/SameKernel>.

Ludo’.