Hi,

Jan Nieuwenhuizen <janneke@gnu.org> skribis:

>> Could it be ‘ifreq-struct-size’ that’s off on GNU/Hurd, or one of its
>> friends?
>
> Something like that: sizeof-ifconf is set to 16 (like on x86_64), but
> it's size should be 8.

Oh, that’s because ‘define-c-struct’ does all the work at
macro-expansion time, with the host types and alignment constraints.  I
wonder how we didn’t notice it earlier.  Cross-compiling from x86_64 to
ARMv7 has the same problem, but maybe the networking ioctls work by
chance.

The patch below appears to fix it:

--8<---------------cut here---------------start------------->8---
$ ./pre-inst-env guild compile --target=i686-pc-linux-gnu guix/build/syscalls.scm -o guix/build/syscalls.go
wrote `guix/build/syscalls.go'
$ guix environment -s i686-linux -C --ad-hoc guile-next -- guile -L . -C .
GNU Guile 3.0.2
Copyright (C) 1995-2020 Free Software Foundation, Inc.

Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
This program is free software, and you are welcome to redistribute it
under certain conditions; type `,show c' for details.

Enter `,help' for help.
scheme@(guile-user)> ,use(guix build syscalls)
scheme@(guile-user)> ,m(guix build syscalls)
scheme@(guix build syscalls)> sizeof-ifconf
$1 = 8
scheme@(guix build syscalls)> %host-type
$2 = "i686-unknown-linux-gnu"
--8<---------------cut here---------------end--------------->8---

Thank you!

Ludo’.