lang/rust: Update to 1.45.1

- Apply the "hard links break `env::current_exe()`" workaround from
  r543251 to lang/rust too
- Force rebuild all consumers for the soundness bug in 1.45.0

Changes:	https://blog.rust-lang.org/2020/07/30/Rust-1.45.1.html
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D25835

lang/rust: Update to 1.45.0

- This Rust release comes with LLVM 10.  Drop the LLVM patches we
  no longer need.
- On FreeBSD 13.0 powerpc64 set the elfv2 ABI explicitly in the
  Rust target instead of patching LLVM.
- Build LLVM with Ninja.  It can shorten the build time slightly.
- Force rebuild all consumers to catch regressions early

Changes:	https://blog.rust-lang.org/2020/07/16/Rust-1.45.0.html
Tested by:	mikael, pkubaj, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D25658

lang/rust-bootstrap: Keep the (amd64-native) cross compilers around

lang/rust: Update to 1.44.1

- Properly fix powerpc64 builds [1]

Changes:	https://blog.rust-lang.org/2020/06/18/Rust.1.44.1.html
PR:		247307 [1]
Submitted by:	pkubaj [1]
Reviewed by:	mikael, pkubaj, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D25297

lang/rust-bootstrap: Limit elfv1 bootstrap to GCC9 for now

To use newer GCC the powerpc64 binary package that provides gcc
libraries in the cross sysroot will need updating to a newer GCC
as well.

PR:		246700

lang/rust-bootstrap: Rebuild after r538194

lang/rust: Update to 1.44.0

- Remove devel/cargo-tree since it is now integrated into cargo
- Add patch to fix build with LibreSSL 3.1.x and 3.2.0 [1]
- Force rebuild all consumers to catch regressions early

Changes:	https://blog.rust-lang.org/2020/06/04/Rust-1.44.0.html
PR:		246332 [1]
Tested by:	mikael, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D25099

lang/rust: Update to 1.43.1

- Remove upstreamed patches
- On ppc64 revert e82ec2315e5adb1c291c3702cd2ac1f46ecd0fcf to fix segfaults

Changes:	https://blog.rust-lang.org/2020/05/07/Rust.1.43.1.html
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D24734

lang/rust: Update to 1.43.0

- Add workaround to fix build when CC/CXX have "clang" in them [1]
- Respect AR to fix build with external toolchains [2]
- Force rebuild all consumers to catch regressions early

Changes:	https://blog.rust-lang.org/2020/04/23/Rust-1.43.0.html
PR:		238556 [1], 245583 [2]
Reported by:	Matthias Apitz <guru@unixarea.de> [1], Greg V
<greg@unrelenting.technology> [2]
Tested by:	mikael, pkubaj, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D24521

lang/rust: Update to 1.42.0

- Force rebuild all consumers to catch regressions early

Changes:	https://blog.rust-lang.org/2020/03/12/Rust-1.42.html
Tested by:	mikael, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D24020

lang/rust: Update to 1.41.1

- Force rebuild all consumers to fix potential miscompilations with
  1.41.0
- Enable SOURCES by default.  The sources are indexed by RLS and
  required for it to function properly, so they should be available
  by default.  This also makes sure we test the option properly.
- Remove implied --config=config.toml from x.py args
- Switch to the upstreamed backtrace crate patches like rust-nightly
- Enable WASM by default [0]
- Strip libraries (D23650) [1]
- Simplify plist generation (D23735) [2]

Changes:	https://blog.rust-lang.org/2020/02/27/Rust-1.41.1.html
Submitted by:	mikael [0,1,2]
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D23835

New port: lang/rust-bootstrap

This port creates the required bootstrap compilers for building the
next version of lang/rust.

Thanks to garga, mikael, pkubaj for test building lang/rust with
the generated bootstraps.

Approved by:	portmgr (mat, flavors)
Differential Revision:	https://reviews.freebsd.org/D23133