libzstd: Explicitly define ZSTD_DISABLE_ASM

On FreeBSD, ZSTD_ASM_SUPPORTED is defined as 0, but on macOS and Linux
it is defined as 1, yet we don't build any of the assembly sources.
Rather than add them just for bootstrapping on non-FreeBSD, explicitly
define ZSTD_DISABLE_ASM so they're not needed and everything is
consistent.

This fixes building a bootstrap LLVM toolchain on non-FreeBSD amd64 (the
only architecture with assembly available).

Reviewed by: emaste, imp
Differential Revision: https://reviews.freebsd.org/D41543

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Disable clang 14 warning about bitwise operators in zstd

Parts of zstd, used in openzfs and other places, trigger a new clang 14
-Werror warning:

```
sys/contrib/zstd/lib/decompress/huf_decompress.c:889:25: error: use of bitwise '&' with boolean operands [-Werror,-Wbitwise-instead-of-logical]
(BIT_reloadDStreamFast(&bitD1) == BIT_DStream_unfinished)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

While the warning is benign, it should ideally be fixed upstream and
then vendor-imported, but for now silence it selectively.

MFC after: 3 days

libprivatezstd: Restrict symbol visibility similar to upstream

We have to relax three symbols to dynamically link zstd(1), but the rest
are the same.

pkgbase: Move libprivatezstd from utilities to runtime

libarchive depends on it by default and tar uses libarchive.
So on a update :
1/ runtime contain tar
2/ runtime have libarchive in shlibs_required
3/ libarchive packages depends on utilities
4/ utilities depends on runtime
5/ kaboom

All users of libprivatezstd (libarchive related stuff and objcopy/ar)
are already in utilities.

Discussed with: bapt

Only set WARNS if not defined

This would allow interested parties to do experimental runs with an
environment set appropriately to raise all the warnings throughout the
build; e.g. env WARNS=6 NO_WERROR=yes buildworld.

Not currently touching the numerous instances in ^/tools.

MFC after: 1 week

Update to Zstandard 1.3.7

Relnotes: yes
Sponsored by: Dell EMC Isilon

lib(private)zstd: Fix riscv build

Link __bswap[ds]i2() intrinsics in to libzstd for riscv, where the C runtime
apparently lacks such intrinsics.

Broken in r330894.

Reported by: asomers
Sponsored by: Dell EMC Isilon

Addd work around for LLVM bug 35023.

Clang crashes when compiling zstd_compress.c with optimization for ARM targets.
https://bugs.llvm.org/show_bug.cgi?id=35023

Move zstd from contrib to sys/contrib so it can be used in the
kernel. Adjust the Makefiles that referenced it to the new path.

Sponsored by: Netflix
OK'd by: cem@ and AllanJude@

Follow up on zstd update

Build zstandard with threading enabled