rust186: add a package for rust 1.86.0.

Upstream changes relative to 1.85.1:

Version 1.86.0 (2025-04-03)
==========================

Language
--------
- [Stabilize upcasting trait objects to supertraits.]
  (rust-lang/rust#134367)
- [Allow safe functions to be marked with the `#[target_feature]` attribute.]
  (rust-lang/rust#134090)
- [The `missing_abi` lint now warns-by-default.]
  (rust-lang/rust#132397)
- Rust now lints about double negations, to catch cases that might
  have intended to be a prefix decrement operator (`--x`) as written
  in other languages. This was previously a clippy lint,
  `clippy::double_neg`, and is [now available directly in Rust as
  `double_negations`.]
  (rust-lang/rust#126604)
- [More pointers are now detected as definitely not-null based on
  their alignment in const eval.]
  (rust-lang/rust#133700)
- [Empty `repr()` attribute applied to invalid items are now
  correctly rejected.]
  (rust-lang/rust#133925)
- [Inner attributes `#![test]` and `#![rustfmt::skip]` are no longer
  accepted in more places than intended.]
  (rust-lang/rust#134276)

Compiler
--------
- [Debug-assert that raw pointers are non-null on access.]
  (rust-lang/rust#134424)
- [Change `-O` to mean `-C opt-level=3` instead of `-C opt-level=2`
  to match Cargo's defaults.]
  (rust-lang/rust#135439)
- [Fix emission of `overflowing_literals` under certain macro environments.]
  (rust-lang/rust#136393)

Platform Support
----------------
- [Replace `i686-unknown-redox` target with `i586-unknown-redox`.]
  (rust-lang/rust#136698)
- [Increase baseline CPU of `i686-unknown-hurd-gnu` to Pentium 4.]
  (rust-lang/rust#136700)
- New tier 3 targets:
  - [`{aarch64-unknown,x86_64-pc}-nto-qnx710_iosock`]
    (rust-lang/rust#133631).
    For supporting Neutrino QNX 7.1 with `io-socket` network stack.
  - [`{aarch64-unknown,x86_64-pc}-nto-qnx800`]
    (rust-lang/rust#133631).
    For supporting Neutrino QNX 8.0 (`no_std`-only).
  - [`{x86_64,i686}-win7-windows-gnu`]
    (rust-lang/rust#134609).
    Intended for backwards compatibility with Windows 7.
    `{x86_64,i686}-win7-windows-msvc` are the Windows MSVC counterparts
    that already exist as Tier 3 targets.
  - [`amdgcn-amd-amdhsa`](rust-lang/rust#134740).
  - [`x86_64-pc-cygwin`](rust-lang/rust#134999).
  - [`{mips,mipsel}-mti-none-elf`]
    (rust-lang/rust#135074).
    Initial bare-metal support.
  - [`m68k-unknown-none-elf`](rust-lang/rust#135085).
  - [`armv7a-nuttx-{eabi,eabihf}`, `aarch64-unknown-nuttx`, and
    `thumbv7a-nuttx-{eabi,eabihf}`]
    (rust-lang/rust#135757).

Refer to Rust's [platform support page][platform-support-doc]
for more information on Rust's tiered platform support.

Libraries
---------
- The type of `FromBytesWithNulError` in `CStr::from_bytes_with_nul(bytes:
  &[u8]) -> Result<&Self, FromBytesWithNulError>` was [changed from
  an opaque struct to an enum]
  (rust-lang/rust#134143), allowing users
  to examine why the conversion failed.
- [Remove `RustcDecodable` and `RustcEncodable`.]
  (rust-lang/rust#134272)
- [Deprecate libtest's `--logfile` option.]
  (rust-lang/rust#134283)
- [On recent versions of Windows, `std::fs::remove_file` will now
  remove read-only files.]
  (rust-lang/rust#134679)

Stabilized APIs
---------------

- [`{float}::next_down`]
  (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_down)
- [`{float}::next_up`]
  (https://doc.rust-lang.org/stable/std/primitive.f64.html#method.next_up)
- [`<[_]>::get_disjoint_mut`]
  (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_mut)
- [`<[_]>::get_disjoint_unchecked_mut`]
  (https://doc.rust-lang.org/stable/std/primitive.slice.html#method.get_disjoint_unchecked_mut)
- [`slice::GetDisjointMutError`]
  (https://doc.rust-lang.org/stable/std/slice/enum.GetDisjointMutError.html)
- [`HashMap::get_disjoint_mut`]
  (https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_mut)
- [`HashMap::get_disjoint_unchecked_mut`]
  (https://doc.rust-lang.org/std/collections/hash_map/struct.HashMap.html#method.get_disjoint_unchecked_mut)
- [`NonZero::count_ones`]
  (https://doc.rust-lang.org/stable/std/num/struct.NonZero.html#method.count_ones)
- [`Vec::pop_if`]
  (https://doc.rust-lang.org/std/vec/struct.Vec.html#method.pop_if)
- [`sync::Once::wait`]
  (https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait)
- [`sync::Once::wait_force`]
  (https://doc.rust-lang.org/stable/std/sync/struct.Once.html#method.wait_force)
- [`sync::OnceLock::wait`]
  (https://doc.rust-lang.org/stable/std/sync/struct.OnceLock.html#method.wait)

These APIs are now stable in const contexts:

- [`hint::black_box`]
  (https://doc.rust-lang.org/stable/std/hint/fn.black_box.html)
- [`io::Cursor::get_mut`]
  (https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.get_mut)
- [`io::Cursor::set_position`]
  (https://doc.rust-lang.org/stable/std/io/struct.Cursor.html#method.set_position)
- [`str::is_char_boundary`]
  (https://doc.rust-lang.org/stable/std/primitive.str.html#method.is_char_boundary)
- [`str::split_at`]
  (https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at)
- [`str::split_at_checked`]
  (https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_checked)
- [`str::split_at_mut`]
  (https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut)
- [`str::split_at_mut_checked`]
  (https://doc.rust-lang.org/stable/std/primitive.str.html#method.split_at_mut_checked)

Cargo
-----
- [When merging, replace rather than combine configuration keys
  that refer to a program path and its arguments.]
  (rust-lang/cargo#15066)
- [Error if both `--package` and `--workspace` are passed but the
  requested package is missing.]
  (rust-lang/cargo#15071) This was previously
  silently ignored, which was considered a bug since missing packages
  should be reported.
- [Deprecate the token argument in `cargo login` to avoid shell history leaks.]
  (rust-lang/cargo#15057)
- [Simplify the implementation of `SourceID` comparisons.]
  (rust-lang/cargo#14980) This may
  potentially change behavior if the canonicalized URL compares
  differently in alternative registries.

Rustdoc
-----
- [Add a sans-serif font setting.]
  (rust-lang/rust#133636)

Compatibility Notes
-------------------
- [The `wasm_c_abi` future compatibility warning is now a hard error.]
  (rust-lang/rust#133951)
  Users of `wasm-bindgen` should upgrade to at least version 0.2.89,
  otherwise compilation will fail.
- [Remove long-deprecated no-op attributes `#![no_start]` and `#![crate_id]`.]
  (rust-lang/rust#134300)
- [The future incompatibility lint `cenum_impl_drop_cast` has been
  made into a hard error.]
  (rust-lang/rust#135964) This means it is
  now an error to cast a field-less enum to an integer if the enum
  implements `Drop`.
- [SSE2 is now required for "i686" 32-bit x86 hard-float targets;
  disabling it causes a warning that will become a hard error
  eventually.]
  (rust-lang/rust#137037) To compile for
  pre-SSE2 32-bit x86, use a "i586" target instead.

Internal Changes
----------------

These changes do not affect any public interfaces of Rust, but they represent
significant improvements to the performance or internals of rustc and related
tools.

- [Build the rustc on AArch64 Linux with ThinLTO + PGO.]
  (rust-lang/rust#133807)
  The ARM 64-bit compiler (AArch64) on Linux is now optimized with
  ThinLTO and PGO, similar to the optimizations we have already
  performed for the x86-64 compiler on Linux. This should make it
  up to 30% faster.

Author: he32

rust186/DESCR

@@ -0,0 +1,13 @@
+Rust is a systems programming language focused on three goals: safety,
+speed, and concurrency.  It maintains these goals without having a
+garbage collector, making it a useful language for a number of use cases
+other languages aren't good at: embedding in other languages, programs
+with specific space and time requirements, and writing low-level code,
+like device drivers and operating systems.
+
+It improves on current languages targeting this space by having a number
+of compile-time safety checks that produce no runtime overhead, while
+eliminating all data races.  Rust also aims to achieve "zero-cost
+abstractions" even though some of these abstractions feel like those of
+a high-level language.  Even then, Rust still allows precise control
+like a low-level language would.

rust186/HOWTO-BOOTSTRAP

@@ -0,0 +1,85 @@
+How to build a rust bootstrap kit using pkgsrc
+----------------------------------------------
+
+A rust bootstrap kit is simply a pre-compiled binary of rust and
+the rust standard library, and contains the "rust" and "rust-std"
+build results, found in
+
+   work/rustc-<version>/build/dist/
+as
+   rust-<version>-<target>.tar.xz
+and
+   rust-std-<version>-<target>.tar.xz
+
+These result files are produced when the "dist" build target is
+used, ref. BUILD_TARGET.   For a normal native build of the rust
+pkgsrc package, the default BUILD_TARGET is "build", not "dist".
+
+There are two possible ways to produce a bootstrap kit:
+
+1) a native build.  This requires minimum preparation, except
+   possibly for setting rust.BUILD_TARGET to "dist" via e.g.
+   /etc/mk.conf.  Note that on NetBSD, using the "BUILD_TARGET" ==
+   "dist" results in the "rust-cargo-static" option being set, ref.
+   options.mk.  This is so that the resulting bootstrap kits are
+   built with mostly-static linking, reducing the run-time dependencies
+   of the bootstrap kits.
+
+2) a cross-build.  This requires a bit of preparation:
+
+   For each target you want to cross-build rust for, you need
+     - the cross toolchain resulting from "build.sh tools" for
+       the intended target
+     - an OS distribution extracted, including the comp.tgz
+       set so that the target's include files can be used
+     - for 32-bit ports, the "libatomic" package needs to be
+       available.  I'm sure there's a clever and long-winded
+       use of pkg_install which can be used to effect this;
+       I on my hand have always just extracted the tgz file
+       and done the minimal cleanup of the "cruft" files
+       which are part of the package meta-data.
+     - Pick a root directory for the target, e.g. /u/i386.
+       Below this directory place the "tools" containing
+       the cross-compiler in a "tools" sub-directory.
+       Similarly, the extracted OS distribution in the "dest"
+       sub-directory.
+
+   There are two methods available for doing the cross-compile:
+
+   a) Using the "cross.mk" file.  For an i386 build against i586, the
+      following settings should be active:
+
+CROSS_ROOT=            /u/i386
+MAKE_ENV+=             CROSS_ROOT=${CROSS_ROOT}
+GNU_CROSS_TARGET=      i486--netbsdelf
+MAKE_ENV+=             GNU_CROSS_TARGET=${GNU_CROSS_TARGET}
+TARGET=                i586-unknown-netbsd
+SCRIPTS=               ${WRKDIR}/scripts
+CONFIGURE_ARGS+=       --host=${TARGET}
+CONFIGURE_ARGS+=       --target=${TARGET}
+CONFIGURE_ARGS+=       --set=target.${TARGET}.cc=${SCRIPTS}/gcc-wrap
+CONFIGURE_ARGS+=       --set=target.${TARGET}.cxx=${SCRIPTS}/c++-wrap
+CONFIGURE_ARGS+=       --set=target.${TARGET}.linker=${SCRIPTS}/gcc-wrap
+CONFIGURE_ARGS+=       --set=target.${TARGET}.ar=${CROSS_ROOT}/tools/bin/${GNU_CROSS_TARGET}-ar
+
+      Then doing a "make" will cross-build rust, including the LLVM
+      embedded in the rust distribution, ref. the defaulting of that
+      option when TARGET is defined ref. options.mk.
+
+      Note that when TARGET is set, the default build target for
+      the rust makefile becomes "dist", so there's no need to set
+      rust.BUILD_TARGET for cross-builds.
+
+   b) Using the "do-cross.mk" Makefile.  This will attempt to
+      cross-build rust for all the targets listed in the SHORT_TARGETS
+      variable in that file.  Overriding the root directories for
+      the various targets can be done by making your own "local-roots.mk"
+      file, ref. "do-cross.mk".
+
+      This will create a "dist" subdirectory in the rust pkgsrc
+      directory, and the bootstrap kits for each architecture, plus
+      the library source kit will be placed in this directory.
+
+The bootstrap kits can then be placed in /usr/pkgsrc/distfiles, and
+be used by the "next" rust version, where you can use "make makesum"
+to compute the updated checksums for the bootstrap kits.