librustc: Allow linkage attribute on any statics, not just foreign statics.
librustc: Respect no-compiler-rt target option for static libs as well.
Add `Show` and `Clone` trait to arrays

Due to not being able to parametrize over array sizes, `Clone` is only
implemented for element types that are `Copy`able.
libstd: improve os::args() doc
Guide: add a pointer to play.rust-lang.org and explain how to run the code examples.
Fixed several typos in libcollections
Implement more basic traits for the marker types.
Fixed a few typos in libcore
Disallow parsing of struct variants with 0 fields

Make struct variant syntax more consistent with struct syntax and fix an
assert in middle::typeck.

Fix #19003
doc: extend a893397 to make whole document consistent
slightly better deprecation message for fn syntax
change return type of slice_shift_char

`slice_shift_char` splits a `str` into it's leading `char` and the remainder
of the `str`. Currently, it returns a `(Option<char>, &str)` such that:

    "bar".slice_shift_char() => (Some('b'), "ar")
    "ar".slice_shift_char()  => (Some('a'), "r")
    "r".slice_shift_char()   => (Some('r'), "")
    "".slice_shift_char()    => (None,      "")

This is a little odd. Either a `str` can be split into both a head and a
tail or it cannot. So the return type should be `Option<(char, &str)>`.
With the current behaviour, in the case of the empty string, the `str`
returned is meaningless - it is always the empty string.

This commit changes slice_shift_char so that:

    "bar".slice_shift_char() => Some(('b', "ar"))
    "ar".slice_shift_char()  => Some(('a', "r"))
    "r".slice_shift_char()   => Some(('r', ""))
    "".slice_shift_char()    => None

[breaking-change]
libgraphviz: Id::new returns Result<Id, ()> instead of panicking on error

creating a new Id object requires the format to match a subset of `ID` format defined by the DOT language. When the format did not match, the function called assert. This was not mentioned in the docs or the spec. I made the failure explicit by returning an Result<Id, ()>.
auto merge of #19007 : huonw/rust/more-marker-impls, r=alexcrichton

Useful for #[deriving].
Switch to purely namespaced enums

This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:

```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
=>
```
pub use self::Foo::{A, B};

pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
or
```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = Foo::A;
}
```

[breaking-change]
Bring back the dylib kind of the link attribute
Don't inherit stability to items in a function body.

Items defined in the body of a function has no visibility
outside it, and thus have no reason to be marked with
stability attributes.

Closes #17488
Remove duplicate code by using util::copy()
Return proper errors with update_err
auto merge of #18973 : sfackler/rust/enum-namespace-pt2, r=pcwalton

This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:

```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
=>
```
pub use self::Foo::{A, B};

pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
or
```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = Foo::A;
}
```

[breaking-change]