pkg/59609: zstandard-0.24.0 seems to unconditionally access qsort_r() that may not be available on older NetBSD

[leot%NetBSD.org@localhost]

>Number:         59609
>Category:       pkg
>Synopsis:       zstandard-0.24.0 seems to unconditionally access qsort_r() that may not be available on older NetBSD
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Aug 26 13:25:00 +0000 2025
>Originator:     Leonardo Taccari
>Release:        NetBSD 10.99.11
>Organization:
The NetBSD Foundation
>Environment:
System: NetBSD boh 10.99.11 NetBSD 10.99.11 (GENERIC) #0: Sat Aug 3 22:42:39 CEST 2024 leot@abacus:/usr/obj/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
Trying to import zstandard package on systems without qsort_r(3) (at
least an old NetBSD-current, probably relevant for netbsd-10 and
netbsd-9 too and maybe other platforms) it seems to unconditionally
access undefined qsort_r().

Please note that this is a regression of py-zstandard-0.24.0,
py-zstandard-0.23.0nb2 worked fine.
>How-To-Repeat:
$ python3 -c 'import zstandard'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/usr/pkg/lib/python3.12/site-packages/zstandard/__init__.py", line 44, in <module>
    from .backend_c import *  # type: ignore
    ^^^^^^^^^^^^^^^^^^^^^^^^
ImportError: /usr/pkg/lib/python3.12/site-packages/zstandard/backend_c.so: Undefined PLT symbol "qsort_r" (symnum = 97)
>Fix:
Yes, please!