bug#54292: Commit e8518c43 breaks guix pull on i686

[Diego Nicola Barbato]

Hi Guix,

Commit e8518c43 (gnu: Add stex) breaks guix pull, specifically the
package cache hook, on i686-linux.  I.e. the following command

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guix pull --commit=e8518c43 --system=i686-linux -p /tmp/guix
--8<---------------cut here---------------end--------------->8---

fails like this:

--8<---------------cut here---------------start------------->8---

[...]

building package cache...
/builder for 
`/gnu/store/f1j059k0x7hpqmhwgyar6761c6jrw4iw-guix-package-cache.drv' failed to 
produce output path 
`/gnu/store/0z272l1izcm45ynwfzz5vvnnhg4ik1ij-guix-package-cache'
build of /gnu/store/f1j059k0x7hpqmhwgyar6761c6jrw4iw-guix-package-cache.drv 
failed
View build log at 
'/var/log/guix/drvs/f1/j059k0x7hpqmhwgyar6761c6jrw4iw-guix-package-cache.drv.gz'.
cannot build derivation 
`/gnu/store/cm9wh5fv3a94cbpb839dhbf2wf31zg7r-profile.drv': 1 dependencies 
couldn't be built
guix pull: error: build of 
`/gnu/store/cm9wh5fv3a94cbpb839dhbf2wf31zg7r-profile.drv' failed
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The build log looks like this:

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(repl-version 0 1 1)
Generating package cache for 
'/gnu/store/dzcm0fk5a41bwmhy74sv0v2bvmapx5qy-profile'...
(exception wrong-type-arg (value "string-ref") (value "Wrong type argument in 
position ~A (expecting ~A): ~S") (value (1 "string" #f)) (value (#f)))
--8<---------------cut here---------------end--------------->8---

This issue was introduced by commit e8518c43 and is still present on
current master (commit 6c3c4f70).

Regards,

Diego