This reverts commit dc03f6290f5b9bd3d50c7e12e58dee870889d599.
OpenBSD 7.6 will support elf_aux_info(3), and the detection code used
on FreeBSD will work on OpenBSD 7.6 too. Keep things simpler and drop
the OpenBSD-specific sysctl() method.
Thanks to Christian Weisgerber.
The C code is from Christian Weisgerber, I merely reordered the OSes.
Then I added the build system checks without testing them.
Also thanks to Brad Smith who submitted a similar patch on GitHub
a few hours after Christian had sent his via email.
Co-authored-by: Christian Weisgerber <naddy@mips.inka.de>
Closes: https://github.com/tukaani-project/xz/pull/125
Even though the proper name for the architecture is aarch64, this
project uses ARM64 throughout. So the rename is for consistency.
Additionally, crc32_arm64.h was slightly refactored for the following
changes:
* Added MSVC, FreeBSD, and macOS support in
is_arch_extension_supported().
* crc32_arch_optimized() now checks the size when aligning the
buffer.
* crc32_arch_optimized() loop conditions were slightly modified to
avoid both decrementing the size and incrementing the buffer
pointer.
* Use the intrinsic wrappers defined in <arm_acle.h> because GCC and
Clang name them differently.
* Minor spacing and comment changes.
