Apply lint attrs to individual "use" declarations

Fixes #10534
Register new snapshots

These are the first successful snapshots after the LLVM upgrade, built with LLVM
that requires C++11
Fix Vim indent regressions from #13600.

The change in #13600 was incorrect, containing a bad regular expression;
inside an indent function, errors are silently ignored (and the ``~=``
operation will return 0), so it just always failed, causing the cases
that were supposed to be caught to not be caught and making things like
the ``match`` example shown above or struct field definitions regress.

I have fixed the regular expression to what it should have been. This is
still imperfect, of course, not handling cases like where the first
argument to a function is a function call (``foo(bar(),``), but it'll do
for now.
Update libuv

This update brings a few months of changes, but primarily a fix for the
following situation.

When creating a handle to stdin, libuv used to set the stdin handle to
nonblocking mode. This would end up affect this stdin handle across all
processes that shared it, which mean that stdin become nonblocking for everyone
using the same stdin. On linux, this also affected *stdout* because stdin/stdout
roughly point at the same thing.

This problem became apparent when running the test suite manually on a local
computer. The stdtest suite (running with libgreen) would set stdout to
nonblocking mode (as described above), and then the next test suite would always
fail for a printing failure (because stdout was returning EAGAIN).

This has been fixed upstream, joyent/libuv@342e8c, and this update pulls in this
fix. This also brings us in line with a recently upstreamed libuv patch.

Closes #13336
Closes #13355
test: Add an option to not capture output

A new flag to the test runner, --nocapture, can be passed to instruct that the
output of tests should not be captured by default. The behavior can also be
triggered via a RUST_TEST_NOCAPTURE environment variable being set.

Closes #13374
auto merge of #13619 : alexcrichton/rust/update-libuv, r=brson

This update brings a few months of changes, but primarily a fix for the
following situation.

When creating a handle to stdin, libuv used to set the stdin handle to
nonblocking mode. This would end up affect this stdin handle across all
processes that shared it, which mean that stdin become nonblocking for everyone
using the same stdin. On linux, this also affected *stdout* because stdin/stdout
roughly point at the same thing.

This problem became apparent when running the test suite manually on a local
computer. The stdtest suite (running with libgreen) would set stdout to
nonblocking mode (as described above), and then the next test suite would always
fail for a printing failure (because stdout was returning EAGAIN).

This has been fixed upstream, joyent/libuv@342e8c, and this update pulls in this
fix. This also brings us in line with a recently upstreamed libuv patch.

Closes #12827
Closes #13336
Closes #13355
fix O(n^2) perf bug for std::io::fs::walk_dir

The `walk_dir` iterator was simulating a queue using a vector (in particular, using `shift`),
leading to O(n^2) performance. Since the order was not well-specified (see issue #13411),
the simplest fix is to use the vector as a stack (and thus yield a depth-first traversal).
This patch does exactly that.  It leaves the order as originally specified -- "some top-down
order" -- and adds a test to ensure a top-down traversal.

Note that the underlying `readdir` function does not specify any particular order, nor
does the system call it uses.

Closes #13411.
auto merge of #13706 : alexcrichton/rust/test-nocapture, r=brson

A new flag to the test runner, --nocapture, can be passed to instruct that the
output of tests should not be captured by default. The behavior can also be
triggered via a RUST_TEST_NOCAPTURE environment variable being set.

Closes #13374
auto merge of #13720 : aturon/rust/walk_dir-perf, r=alexcrichton

The `walk_dir` iterator was simulating a queue using a vector (in particular, using `shift`),
leading to O(n^2) performance. Since the order was not well-specified (see issue #13411),
the simplest fix is to use the vector as a stack (and thus yield a depth-first traversal).
This patch does exactly that, and adds a test checking for depth-first behavior.

Note that the underlying `readdir` function does not specify any particular order, nor
does the system call it uses.

Closes #13411.
auto merge of #13729 : chris-morgan/rust/fix-vim-indent, r=alexcrichton

The change in #13600 was incorrect, containing a bad regular expression;
inside an indent function, errors are silently ignored (and the ``~=``
operation will return 0), so it just always failed, causing the cases
that were supposed to be caught to not be caught and making things like
the ``match`` example shown above or struct field definitions regress.

I have fixed the regular expression to what it should have been. This is
still imperfect, of course, not handling cases like where the first
argument to a function is a function call (``foo(bar(),``), but it'll do
for now.

----

I have a general request to make of reviewers about any changes made to `src/etc/vim`: **please tell me**. As a general rule I want to review them. (I’ll make an exception for changes the prelude; it needs fixing from time to time when some people don’t update the syntax file, anyway.)

cc @brandonw
native: Remove unused and untested UnixDatagram
std: Add timeouts to unix connect/accept

This adds support for connecting to a unix socket with a timeout (a named pipe
on windows), and accepting a connection with a timeout. The goal is to bring
unix pipes/named sockets back in line with TCP support for timeouts.

Similarly to the TCP sockets, all methods are marked #[experimental] due to
uncertainty about the type of the timeout argument.

This internally involved a good bit of refactoring to share as much code as
possible between TCP servers and pipe servers, but the core implementation did
not change drastically as part of this commit.

cc #13523
auto merge of #13671 : dcrewi/rust/lint-directives-on-use-items, r=alexcrichton

Fixes #10534
auto merge of #13711 : alexcrichton/rust/snapshots, r=brson

These are the first successful snapshots after the LLVM upgrade, built with LLVM
that requires C++11
auto merge of #13723 : alexcrichton/rust/pipe-connect-timeout, r=brson

This adds support for connecting to a unix socket with a timeout (a named pipe
on windows), and accepting a connection with a timeout. The goal is to bring
unix pipes/named sockets back in line with TCP support for timeouts.

Similarly to the TCP sockets, all methods are marked #[experimental] due to
uncertainty about the type of the timeout argument.

This internally involved a good bit of refactoring to share as much code as
possible between TCP servers and pipe servers, but the core implementation did
not change drastically as part of this commit.

cc #13523
test: Enable extern-fn-reachable test

It didn't work because it tried to call itself but symbols are not
exported as default in executables.

Note that `fun5` is not internal anymore since it is in library.
test: Remove/update some old ignored tests