Update to 3.0.0 release and transition from parity-ethereum to openethereum.

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

Unbreak librocksdb-sys crate build after LLVM 10 import

In file included from rocksdb/utilities/backupable/backupable_db.cc:16:
rocksdb/util/channel.h:35:33: error: no matching constructor for initialization
of 'std::lock_guard<std::mutex>'
    std::lock_guard<std::mutex> lk(lock_);
                                ^  ~~~~~
/usr/include/c++/v1/__mutex_base:90:14: note: candidate constructor not viable:
1st argument ('const std::mutex') would lose const qualifier
    explicit lock_guard(mutex_type& __m)
_LIBCPP_THREAD_SAFETY_ANNOTATION(acquire_capability(__m))
             ^
/usr/include/c++/v1/__mutex_base:100:5: note: candidate constructor not viable:
no known conversion from 'const std::mutex' to 'const
std::__1::lock_guard<std::__1::mutex>' for 1st argument
    lock_guard(lock_guard const&) _LIBCPP_EQUAL_DELETE;
    ^
/usr/include/c++/v1/__mutex_base:94:5: note: candidate constructor not viable:
requires 2 arguments, but 1 was provided
    lock_guard(mutex_type& __m, adopt_lock_t)
_LIBCPP_THREAD_SAFETY_ANNOTATION(requires_capability(__m))
    ^
1 error generated.

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

Update to 2.7.2 release.

Update to 2.7.1 release.

lang/rust: Update to 1.41.0

- Force rebuild all consumers to catch regressions early
- Switch to cross-compiled (from amd64) bootstraps for all
  architectures generated with the incoming lang/rust-bootstrap
- Update cargo-c to 0.5.2 to unbreak librav1e build
- Make use of regular MAKE_ENV/TEST_ENV in lang/rust
- Turn on RUST_BACKTRACE in lang/rust and USES=cargo to hopefully
  produce more useful failure logs when something panics during
  builds

Changes:	https://blog.rust-lang.org/2020/01/30/Rust-1.41.0.html
Tested by:	mikael, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D23385

Update to 2.7.0 release.

lang/rust: Update to 1.40.0

- Force rebuild all consumers to catch regressions early

Thanks to Mikael Urankar for providing updated bootstraps for
aarch64, armv6, armv7, powerpc64.

Changes:	https://blog.rust-lang.org/2019/12/19/Rust-1.40.0.html
Tested by:	mikael.urankar@gmail.com, tobik
With hat:	rust
Differential Revision:	https://reviews.freebsd.org/D22843

Update to 2.5.12 release.

Update to 2.5.11 release.

Apparently it can be built only on FreeBSD 12 amd64.

11.3-i386: LLVM ERROR: out of memory
12.0-i386: parity-4c44772188702cce.parity.e8wnuwsj-cgu.11.rcgu.o: file not
recognized: File format not recognized
11.3-amd64: parity-1a336ac89c32de09.parity.5withm3d-cgu.11.rcgu.o: file not
recognized: File format not recognized

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