Look at the version of the script from [1], it has a hard-coded list for
cross-compiling:
[1]
https://sources.debian.org/src/texlive-bin/2025.20250727.75242+ds-4/libs/zziplib/zziplib-src/m4/ax_check_aligned_access_required.m4
That script won't work out of the box because we're not cross-compiling.
But obviously works correctly in the texlive-bin package as could be seen from
the build log I posted.
What’s the difference?
That doesn't make a lot of sense...
If you're not cross-compiling, why would $cross_compiling be set and the case
statement be executed?
But, I gave it the benefit of the doubt, replaced the script with [1], and the result was
that configure bailed out with a syntax error. Looking at the script, it's clear that the
"fi" on line 59 is in the wrong place. It should be on line 58, as it belongs
to the if/else on line 31 and 35. The ]) on line 58 belongs to the AC_CACHE_CHECK on line
29.
I'm not sure how this script is supposed to work for texlive-bin, but it's
obviously broken.