This commit moves compression of the bytecode from the `link` module to the
`write` module, namely allowing it to be (a) cached by incremental compilation
and (b) produced in parallel. The parallelization may show up as some nice wins
during normal compilation and the caching in incremental mode should be
beneficial for incremental compiles! (no more need to recompress the entire
crate's bitcode on all builds)

rustbuild: Don't try to build rustdoc API docs with compiler docs

rustdoc is built separately to rustc now so the docs would need to be
generated separately as well. Also rustdoc doesn't build at stage 1
which prevented the compiler docs being built at stage 1.

Fixes: #44629

Rollup of 6 pull requests

- Successful merges: #45227, #45356, #45407, #45411, #45418, #45419
- Failed merges: #45421

Fix most rendering warnings from switching to CommonMark

There's one big one lift, I'm filing a bug for it soon.

r? @rust-lang/docs

Remove "gender" from code of conduct, keep only "gender identity and expression"

Mirrors https://github.com/rust-lang/rust-www/pull/954 . See that pull
request for motivation.

Reactivate clippy in toolstate.toml

The `Cargo.lock` changes are b/c clippy is not its own workspace anymore, but is part of the main workspace

r? @Manishearth

Fix typos in README.md

Add explanatory text for error E0599

Add a text description of this error instead of just example error code

r? GuillaumeGomez

Expand docs/examples for TCP `set_nonblocking` methods.

Part of https://github.com/rust-lang/rust/issues/44050.

Part of https://github.com/rust-lang/rust/issues/44050.

Update libc and some fixes for x86_64-unknown-linux-gnux32

Add a text description of this error instead of just example error code

Move collector to rustc_trans_utils

std: Update randomness implementation on Windows

This commit updates the OS random number generator on Windows to match the
upstream implementation in the `rand` crate. First proposed in
rust-lang-nursery/rand#111 this implementation uses a "private" API of
`RtlGenRandom`. Despite the [documentation][dox] indicating this is a private
function its widespread use in Chromium and Firefox as well as [comments] from
Microsoft internally indicates that it's highly unlikely to break.

Another motivation for switching this is to also attempt to make progress
on #44911. It may be the case that this function succeeds while the previous
implementation may fail in "weird" scenarios.

[dox]: https://msdn.microsoft.com/en-us/library/windows/desktop/aa387694(v=vs.85).aspx
[comments]: https://github.com/rust-lang-nursery/rand/issues/111#issuecomment-316140155

make `erase_regions_ty` query anonymous

r? @michaelwoerister

rustc: Add `_imp_` symbols later in compilation

On MSVC targets rustc will add symbols prefixed with `_imp_` to LLVM modules to
"emulate" dllexported statics as that workaround is still in place after #27438
hasn't been solved otherwise. These statics, however, were getting gc'd by
ThinLTO accidentally which later would cause linking failures.

This commit updates the location we add such symbols to happen just before
codegen to ensure that (a) they're not eliminated by the optimizer and (b) the
optimizer doesn't even worry about them.

Closes #45347

Make sure to clear out the stageN-{rustc,std,tools} directories.

We copy built tool binaries into a dedicated directory to avoid deleting them,
stageN-tools-bin.  These aren't ever cleared out by code, since there should be
no reason to do so, and we'll simply overwrite them as necessary.

When clearing out the stageN-{std,rustc,tools} directories, make sure to delete
both Cargo directories -- per-target and build scripts. This ensures that
changing libstd doesn't cause problems due to build scripts not being rebuilt,
even though they should be.

Fixes https://github.com/rust-lang/rust/issues/44739.

Mirrors https://github.com/rust-lang/rust-www/pull/954 . See that pull
request for motivation.

Fix a few bugs in drop generation

This fixes a few bugs in drop generation, one of which causes spurious MIR borrowck errors.

Fixes #44832.

r? @EddyB

Print rustdoc rendering warnings all the time

r? @rust-lang/dev-tools

incr.comp.: Use 128bit SipHash for fingerprinting

This PR switches incr. comp. result fingerprinting from 128 bit BLAKE2 to 128 bit SipHash. When we started using BLAKE2 for fingerprinting, the 128 bit version of SipHash was still experimental. Now that it isn't anymore we should be able to get a nice performance boost without significantly increasing collision probability.

~~I'm going to start a try-build for this, so we can gauge the performance impact before merging (hence the `WIP` in the title).~~

EDIT: Performance improvements look as expected. Tests seem to be passing.

Fixes #41215.

Mark block exits as reachable if the block can break.

This only happens when desugaring `catch` expressions for now, but regular blocks (in HIR) can be broken from - respect that when doing reachability analysis.

Fixes #45124.

Refactor `ensure` and `try_get_with`

There was a bit of code shared between `try_get_with` and `ensure`, after I
added `ensure`. I refactored that shared code into a query-agnostic method
called `read_node_index`.

The new method `read_node_index` will attempt to find the node
index (`DepNodeIndex`) of a query. When `read_node_index` finds the
`DepNodeIndex`, it marks the current query as a reader of the node it's
requesting the index of.

This is used by `try_get_with` and `ensure` as it elides the unimportant (to
them) details of if the query is invalidated by previous changed computation (Red)
or new and if they had to mark the query green. For both `try_get_with` and
`ensure`, they just need to know if they can lookup the results or have to
reevaluate.

@nikomatsakis this is the [refactor we discussed](https://github.com/rust-lang/rust/pull/45228#discussion_r144577392) in the comment thread of #45228

Save the highlighted item when switching tab

To be merged after #45281.

r? @rust-lang/docs

This makes it mandatory for other steps to have to handle the potential
failure instead of failing in an odd way later down the road.

Issue 44986/fix windows ui path

#44968

Rollup of 8 pull requests

- Successful merges: #45343, #45349, #45352, #45374, #45375, #45376, #45377, #45382
- Failed merges:

rustbuild: fix dist in debug mode

In debug mode, the artifacts are placed in "debug", so don't hardcode "release" and use our helper to get the right directory name

Fix typos in librustc/ty/README.md

Fix typos in src/librustc/README.md

Allow passing a path with tilde to the configure script

Currently `./configure --local-rust-root=~/.cargo --enable-local-rebuild` fails with
 ```
Exception: no cargo executable found at `~/.cargo//bin/cargo`
```

Remove --enable-rustbuild config option from an example

`--enable-rustbuild` is no longer recognized by the configure script. Also I think we should use `./configure` and `./x.py` instead of `configure` and `../x.py`.

test: Update Emscripten failures/passing

All tests should now have annotation for *why* they're ignored on emscripten. A
few tests no longer need such an annotation as well!

Closes #41299

added examples of closures for str::find

This is an attempt to fix https://github.com/rust-lang/rust/issues/45327

r? @steveklabnik

Make Solaris builder compatible with Solaris 10 retry

Unfortunately, #45255 does not quite cut it,
so use a different approach to have Solaris 10 compatibility
by tricking libbacktrace's autoconf tests.
The sysroot download routine is slightly changed, too.