rustbuild: Fix cross to netbsd from Linux

Apparently the NetBSD compiler-rt builds into the linux directory as well.
I'm... detecting a trend!

documentation fix in RELEASES.md

f32 should probably be denoted as 0.0 as it might improve readability.

docs: `let` introduces a statement

I changes *expression* to *statement* to make more accurate, because in Rust, `let` introduces a declaration statement.

Fix usability problem when browse document locally

You cannot use `history.replaceState` when you browse locally, it breaks the security policy of Chrome and perhaps other browsers.
Closes https://github.com/rust-lang/rust/issues/32307
Thank @crumblingstatue for the help!

docs: One typo

I think it's a mistake of spelling.

Add comment about opt-in nature of compiletest note/help messages.

The opt-in functionality was proposed and discussed in
https://github.com/rust-lang/rust/issues/21195

syntax: impl ToTokens for P<ast::ImplItem>

I'm working on updating zinc for latest rust, and it appears that I need this impl[0].

More generally, I realise that libsyntax is "Whatever the compiler team needs to build a compiler", but should I just open a PR fleshing this out for all types?

https://github.com/hackndev/zinc/blob/master/ioreg/src/builder/setter.rs#L194-L197

FreeBSD has already supported Cargo

Both Packages and Ports of FreeBSD have Cargo in present.

Add intrinsics for float arithmetic with `fast` flag enabled

Add intrinsics for float arithmetic with `fast` flag enabled

`fast` a.k.a UnsafeAlgebra is the flag for enabling all "unsafe"
(according to llvm) float optimizations.

See LangRef for more information http://llvm.org/docs/LangRef.html#fast-math-flags

Providing these operations with less associativity rules (for example)
is useful to numerical applications.

For example, the summation loop:

    let sum = 0.;
    for element in data {
        sum += *element;
    }

Using the default floating point semantics, this loop expresses that the
floats must be added in a sequence, one after another. This constraint
is usually completely unintended, and it means that no auto-vectorization
is possible.

Add an impl for From trait

Converts a u8 slice to a Ipv4Addr
More discussion on this here: https://github.com/rust-lang/rfcs/pull/1498#issuecomment-191921655

derive: Avoid emitting provided PartialEq, PartialOrd methods for c-like enums

derive: Avoid emitting provided PartialEq, PartialOrd method for c-like enums

`ne` is completely symmetrical with the method `eq`, and we can save
rust code size and compilation time here if we only emit one of them
when possible.

One case where it's easy to recognize is when it's a C-like enum. Most
other cases can not omit ne, because any value field may have a custom
PartialEq implementation.

Change inherent overlap error to a warning for now, to ease the breakage

Closes #32247

r? @nikomatsakis

`fast` a.k.a UnsafeAlgebra is the flag for enabling all "unsafe"
(according to llvm) float optimizations.

See LangRef for more information http://llvm.org/docs/LangRef.html#fast-math-flags

Providing these operations with less precise associativity rules (for
example) is useful to numerical applications.

For example, the summation loop:

    let sum = 0.;
    for element in data {
        sum += *element;
    }

Using the default floating point semantics, this loop expresses the
floats must be added in a sequence, one after another. This constraint
is usually completely unintended, and it means that no autovectorization
is possible.

Adjustments to the panic hook API

Rename `set_handler` and `take_handler` to `set_hook` and `take_hook` since we're not actually "handling" (i.e. fixing) anything.

Also alter `set_hook` to take a `Box<Fn(&PanicInfo) + 'static + Sync + Send>` rather than a parameterized closure since there's otherwise no easy way to re-register a hook that came from `take_hook`.

cc #30449

r? @aturon

Refactor call & function handling in trans, enable MIR bootstrap.

Non-Rust and Rust ABIs were combined into a common codepath, which means:
* The ugly `__rust_abi` "clown shoes" shim for C->Rust FFI is gone, fixes #10116.
* Methods, *including virtual ones* support non-Rust ABIs, closes #30235.
* Non-Rust ABIs also pass fat pointers in two arguments; the result should be identical.
* Zero-sized types are never passed as arguments; again, behavior shouldn't change.

Additionally, MIR support for calling intrinsics (through old trans) was implemented.
Alongside assorted fixes, it enabled MIR to launch 🚀 and do a *complete* bootstrap.
To try it yourself, `./configure --enable-orbit` *or* `make RUSTFLAGS="-Z orbit"`.

Expose the key of Entry variants for HashMap and BTreeMap.

This PR addresses [issue 1541](https://github.com/rust-lang/rfcs/issues/1541) by exposing the key of `HashMap` and `BTreeMap` entry variants. Basic tests are provided.

Add is_documentation for IPv6

This function returns true if the given IPv6 is reserved for
documentation. Also, reject this block in the is_global check

Apparently the NetBSD compiler-rt builds into the linux directory as well.
I'm... detecting a trend!