…ment to have a better span for the error

A rust-enabled gdb already knows how to display string slices,
structs, tuples, and enums (and after rust-lang#54004, the pretty-printers
can't handle enums at all).  This patch disables these pretty-printers
when gdb is rust-enabled.

The "gdb-pretty-struct-and-enums-pre-gdb-7-7.rs" test is renamed,
because it does not seem to depend on any behavior of that version of
gdb, and because gdb 7.7 is 4 years old now.

Fix missing ',' array element separators and convert NaN's to 0.

As reported in rust-lang#54668 (comment)

Hopefully will speed up CI slightly!

This is a follow up to 8aa9267 which changed the driver to use lld
directly rather than invoking it through Clang. This change ensures
we pass all the necessary flags to lld.

It used to point to the implementation PR.

…, r=alexcrichton

Disable some pretty-printers when gdb is rust-enabled

A rust-enabled gdb already knows how to display string slices,
structs, tuples, and enums (and after rust-lang#54004, the pretty-printers
can't handle enums at all).  This patch disables these pretty-printers
when gdb is rust-enabled.

The "gdb-pretty-struct-and-enums-pre-gdb-7-7.rs" test is renamed,
because it does not seem to depend on any behavior of that version of
gdb, and because gdb 7.7 is 4 years old now.

Fix #[cfg] for step impl on ranges

```#[cfg(target_pointer_witdth = ...)]``` is misspelled

Add std::iter::unfold

This adds an **unstable** ~`std::iter::iterate`~ `std::iter::unfold` function and ~`std::iter::Iterate`~ `std::iter::Unfold` type that trivially wrap a ~`FnMut() -> Option<T>`~ `FnMut(&mut State) -> Option<T>` closure to create an iterator. ~Iterator state can be kept in the closure’s environment or captures.~

This is intended to help reduce amount of boilerplate needed when defining an iterator that is only created in one place. Compare the existing example of the `std::iter` module: (explanatory comments elided)

```rust
struct Counter {
    count: usize,
}

impl Counter {
    fn new() -> Counter {
        Counter { count: 0 }
    }
}

impl Iterator for Counter {
    type Item = usize;

    fn next(&mut self) -> Option<usize> {
        self.count += 1;
        if self.count < 6 {
            Some(self.count)
        } else {
            None
        }
    }
}
```

… with the same algorithm rewritten to use this new API:

```rust
fn counter() -> impl Iterator<Item=usize> {
    std::iter::unfold(0, |count| {
        *count += 1;
        if *count < 6 {
            Some(*count)
        } else {
            None
        }
    })
}
```

-----

This also add unstable `std::iter::successors` which takes an (optional) initial item and a closure that takes an item and computes the next one (its successor).

```rust
let powers_of_10 = successors(Some(1_u16), |n| n.checked_mul(10));
assert_eq!(powers_of_10.collect::<Vec<_>>(), &[1, 10, 100, 1_000, 10_000]);
```

…ichaelwoerister

Ensure that the argument to `static_assert` is a `bool`

cc @eddyb

…i-obk

When popping in CTFE, perform validation before jumping to next statement to have a better span for the error

Currently, when validating the return value fails, the span points at the next statement after the call. That does not make much sense.

r? @oli-obk

Add rustc_codegen_ssa to sysroot

Outside of rustc you are currently unable to use it.

r? @nikomatsakis (because you r+'ed rust-lang#55627)

… r=petrochenkov

Fix json output in the self-profiler

Fix missing ',' array element separators and convert NaN's to 0.

cc @Mark-Simulacrum

Fix invalid bitcast taking bool out of a union represented as a scalar

As reported in rust-lang#54668 (comment)

ci: Download clang/lldb from tarballs

Hopefully will speed up CI slightly!

Add unstable Literal::subspan().

Take 2 of rust-lang#55971. Still ~wrong, but now with a comment! (and less of a surface) Unblocks rust-lang#49219.

r? @alexcrichton

…excrichton

Pass additional linker flags when targeting Fuchsia

This is a follow up to 8aa9267 which changed the driver to use lld
directly rather than invoking it through Clang. This change ensures
we pass all the necessary flags to lld.

std::str Adapt documentation to reality

…, r=pietroalbini

[master] Backport 1.30.1 release notes

Fixes rust-lang#56135

r? @ghost

Fix the tracking issue for hash_raw_entry

It used to point to the implementation PR.