Fixes #18956.

None

Changes std::os::errno to return i32, the return type used by the function being delegated to.

This is my first contribution, so feel free to give me advice. I'll be happy to correct things.

 Stop advertisting the `old_impl_check` feature. We can't ENTIRELY remove it yet, but we don't have to add new uses.

r? @aturon

 Since `tr` converts lowercase to uppercase according to system locale using `LC_CTYPE` environment variable; on some locales, rustup.sh fails to use correct variables names, thus deletes temporarily downloaded files and gives a meaningless error as shown below. This a simple fix which explictly sets `LC_CTYPE` as `C`.

Here is what happens without the fix:
```
➜  projects  curl -s https://static.rust-lang.org/rustup.sh | sudo sh
rustup: CFG_CURL             := /usr/bin/curl (7.22.0)
rustup: CFG_TAR              := /bin/tar (1.26)
rustup: CFG_FILE             := /usr/bin/file (5.09)
rustup: CFG_SHA256SUM        := /usr/bin/sha256sum (256sum)
rustup: CFG_SHASUM           := /usr/bin/shasum (5.61)
rustup:
rustup: processing sh args
rustup:
rustup: CFG_PREFiX           :=
rustup: CFG_DATE             :=
rustup:
rustup: validating sh args
rustup:
rustup: host triple: i686-unknown-linux-gnu
rustup: Downloading https://static.rust-lang.org/dist/rust-nightly-i686-unknown-linux-gnu.tar.gz to /tmp/tmp.Wz6F1ToG5z/rust-nightly-i686-unknown-linux-gnu.tar.gz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  132M  100  132M    0     0  59947      0  0:38:31  0:38:31 --:--:-- 71204
rustup: Downloading https://static.rust-lang.org/dist/rust-nightly-i686-unknown-linux-gnu.tar.gz.sha256
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100   109  100   109    0     0    107      0  0:00:01  0:00:01 --:--:--   169
rustup: Verifying hash
rustup: Extracting /tmp/tmp.Wz6F1ToG5z/rust-nightly-i686-unknown-linux-gnu.tar.gz
install: looking for install programs
install:
install: found mkdir
install: found printf
install: found cut
install: found grep
install: found uname
install: found tr
install: found sed
install: found chmod
install:
install: processing /tmp/tmp.Wz6F1ToG5z/rust-nightly-i686-unknown-linux-gnu/install.sh args
install:
install: CFG_DESTDiR          :=
install: CFG_PREFiX           := /usr/local
install: CFG_LiBDiR           := /lib
install: CFG_MANDiR           := /share/man
install:
install: validating /tmp/tmp.Wz6F1ToG5z/rust-nightly-i686-unknown-linux-gnu/install.sh args
install:
install: verifying platform can run binaries
install: verifying destination is writable
mkdir: cannot create directory `': No such file or directory
install: error: can't write to destination. consider `sudo`.
rustup: error: failed to install Rust
```
Notice how `i` wasn't replaced with `I`.

Rust is installed as usual after the fix. Tested on Ubuntu x86 12.04 LTS.
I'm not exactly sure if setting LC_CTYPE is the best solution, but there's that.

 closes #22388

r? @nikomatsakis
cc @insaneinside

 They now point to the correct locations in std::env

r? @alexcrichton

 Fixes #22386

 Requested by Niko in #22200 (and is good to have anyway)

Requested by Niko in #22200 (and is good to have anyway)

   "body": null,

 Since we don’t have Deprecated stability level anymore, the only other source of information is
deprecated-since version, which conveniently to us, only exists if the symbol is deprecated.

Fixes #21789

 `IntoIterator` now has an extra associated item:

``` rust
trait IntoIterator {
    type Item;
    type IntoIter: Iterator<Self=Self::Item>;
}
```

This lets you bind the iterator \"`Item`\" directly when writing generic functions:

``` rust
// hypothetical change, not included in this PR
impl Extend<T> for Vec<T> {
    // you can now write
    fn extend<I>(&mut self, it: I) where I: IntoIterator<Item=T> { .. }
    // instead of
    fn extend<I: IntoIterator>(&mut self, it: I) where I::IntoIter: Iterator<Item=T> { .. }
}
```

The downside is that now you have to write an extra associated type in your `IntoIterator` implementations:

``` diff
 impl<T> IntoIterator for Vec<T> {
+    type Item = T;
     type IntoIter = IntoIter<T>;

     fn into_iter(self) -> IntoIter<T> { .. }
 }
```

Because this breaks all downstream implementations of `IntoIterator`, this is a [breaking-change]

---

r? @aturon

 `cp -a` is a GNU extension. Use an alternate combinaison of POSIX options
(`-PRp`) that do nearly the same.

The difference is `-a` will preserve context, links and xattr attributes,
whereas `-p` not. But as we use it only for copy a file, there is no
difference in the current context.

 Appears to be just an oversight given it is the only method in a stable trait.

r? @aturon because you did final alpha stabilisation of iterators.

book/syntax-extensions.html was renamed to book/plugins.html,
the link should be also updated.
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>

The Rust Programming Language book has no explanation of what `i32` actually means. I have added an explanation for the first time the reader encounters this type.

@steveklabnik Trying out the Glossary idea.

Added the paragraph about 'complicated words' because I think it would be useful to those contributing to the book. Maybe this should not be here

This snuck through my refactor.

Would it be worth the effort to have a test pass that attempts to lint the code for all targets, even if it's not feasible to actually build and test it?

Fixes #22357

Before and after:

![screenshot from 2015-02-15 15 53 24](https://cloud.githubusercontent.com/assets/679122/6203452/dbde7324-b52b-11e4-8252-da96a44c1cf3.png)

#21568

Without the adjustments the retslot might have the wrong type, e.g. when
the return value is implicitly coerced to a trait object.

Fixes #22346

The book in "hello-world" tells that there are configs for some programs and gives a link to main repo's src/etc. Actually, these configs moved to separate repos some days ago. This PR adds a markdown file with links and moves "hello-world" link about editors to point directly to this new file.

`pipe(2)`, under FreeBSD and OpenBSD return a bidirectionnal pipe. So
reading from the writer would block (waiting data) instead of returning
an error.

like for FreeBSD, disable the test for OpenBSD.

This is a patch for #22291.

PLEASE_BENCH=1 adds --bench to the arguments passed to the executable to be tested. At the moment, compiletest does not accept a --bench argument, because it is not needed for any test in src/test/, even the tests in src/test/bench do not use #[bench].

I have updated the makefile to only add the --bench flag for crate tests. I do not think that changing compiletest add --bench to the run arguments of all compile tests makes sense, because it would mess up tests which check command line arguments. Also the bench option can be added as comment in a compile test as well.

cc https://github.com/rust-lang/rust/issues/22240

It is not totally clear if we should just use whitespace, or if the full
unicode word-breaking algorithm is more correct. If there is demand we
can reconsider this decision (and consider the precise algorithm to use
in detail).

cc #15628.

Implement rules described in rust-lang/rfcs#599.

Fixes https://github.com/rust-lang/rust/issues/22211.

~~Based atop PR https://github.com/rust-lang/rust/pull/22182, so the first few commits (up to and including "Pacify the mercilous nrc") have already been reviewed.~~

Since `tr` converts lowercase to uppercase according to system locale using `LC_CTYPE` environment variable; on some locales, rustup.sh fails to use correct variables names, thus deletes temporarily downloaded files and gives a meaningless error as shown below. This a simple fix which explictly sets `LC_CTYPE` as `C`.

closes #22388

Fixes #22386

They now point to the correct locations in std::env

remove it yet, but we don't have to add new uses.