Merge branch 'libbpf-fix-libbpf_sha256-for-github-compatibility'

Andrii Nakryiko says:

====================
libbpf: fix libbpf_sha256() for Github compatibility

Recent reimplementation of libbpf_sha256() introduced issues for libbpf's
Github mirror due to reliance on linux/unaligned.h header. This patch set
fixes those issues to make libbpf source code compatible with Github mirror
setup.

This patch set starts with a bit of organization: we introduce libbpf_utils.c
as a place for generic internal helpers like libbpf_errstr() and
libbpf_sha256(), and move a few existing helpers there. We also clean up
libbpf_strerror_r(), which seems to be a leftover of some previous
refactorings.

And finally, we move libbpf_sha256() from huge libbpf.c into libbpf_utils.c,
following up with fix ups to make its code more Github-friendly.

v1->v2:
- add missed cpu_to_be32() and be32_to_cpu() conversions inside
  {get/put}_unaligned_be32() macros;
- target bpf tree (Alexei);
- applied Eric's libbpf_sha256 selftest locally and verified it works;

v1:
https://lore.kernel.org/bpf/20250930212619.1645410-1-andrii@kernel.org/
====================

Link: https://patch.msgid.link/20251001171326.3883055-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>