This commit refactors the initial implementation to fit into std and
makes some other changes:

- use MaybeUninit internally in SyncOnceCell
- correctly impl Drop for lazy::Once
- port Lazy::take from once_cell from: matklad/once_cell#100

Co-Authored-By: Paul Dicker <pitdicker@users.noreply.github.com>

A follow-up to rust-lang#74406, this commit merely removes the `shell: bash`
lines where they are explicitly added in favor of setting defaults for
*all* "run" steps.

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>

This will render the src/ci/exec-with-shell.py script more or less
useless, but we're going to replace that by just using the system bash
instead.

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>

Also, promote defaults.run.shell from inside only the primary jobs to
the top level.

The src/ci/exec-with-shell.py wrapper script was formerly used to change
out the shell mid-job by intercepting a CI_OVERRIDE_SHELL environment
variable.  Now, instead, we just set `bash` as the global default across
all jobs, and we also delete the exec-with-shell.py script.

Signed-off-by: Kristofer Rye <kristofer.rye@gmail.com>

Closes rust-lang#69414 (no longer ICEs after rust-lang#74159)

… for enums.

This makes extract_lldb_version has the same version type like
extract_gdb_version.

This is technically a breaking change for rustc-dev users.
But note that rustc-dev is a nightly component.

This commit stops linting against `Box` in `extern "C" fn`s for the
`improper_ctypes_definitions` lint - boxes are documented to be
FFI-safe.

Signed-off-by: David Wood <david@davidtw.co>

Always install when the build succeeds

Fixes rust-lang#74431

Signed-off-by: Marc-Antoine Perennou <Marc-Antoine@Perennou.com>

…ns-boxes, r=davidtwco

improper_ctypes_definitions: allow `Box`

Addresses rust-lang#72700 (comment).

This PR stops linting against `Box` in `extern "C" fn`s for the `improper_ctypes_definitions` lint - boxes are documented to be FFI-safe.

cc @alexcrichton @CryZe

Test codegen of compare_exchange operations

Add a codegen test for compare_exchange to verify that rustc emits expected LLVM IR.

Fix `Safety` docs for `from_raw_parts_mut`

This aligns the wording more with the documentation of e.g. `drop_in_place`, `replace`, `swap` and `swap_nonoverlapping` from `core::ptr`.

Also if the pointer were really only valid for writes, it would be trivial to introduce UB from safe code, after calling `core::slice::from_raw_parts_mut`.

Use intra-doc links in `str` and `BTreeSet`

Fixes rust-lang#32129, fixes  rust-lang#32130

A _slight_ degradation in quality is that the `#method.foo` links would previously link to the same page on `String`'s documentation, and now they will navigate to `str`. Not a big deal IMO, and we can also try to improve that.

rustbuild: drop tool::should_install

Always install when the build succeeds

Fixes rust-lang#74431

…r=Manishearth

Fix for rust-lang#67108

I wanted to tackle a simple issue, and stumbled upon rust-lang#67108: this pr removes the function which was exported to the external crate as required in the todo/issue.
I've tested it with:
```
./x.py build --stage 1 --keep-stage 1 src/librustc_codegen_ssa
```
And it looks like it's compiling