configure: Recognize i686 build on msys2
Add support for trailing commas in more places

This lets the parser understand trailing commas in method calls, method
definitions, enum variants, and type parameters.

Closes #14240.
Closes #15887.
test: Convert Window path to MSYS path

When MSYS shell executes program, if its arguments look like MSYS paths,
MSYS automatically converts them into Windows paths.
For example, `/c/path:/d/path` becomes `C:\path;D:\path`.
However, if there is only one path e.g. `/c/path`, it becomes `C:/path`.

maketest.py reverts the behavior to reduce confusion between MSYS and
Windows, but it didn't handle the `/c/path` case. This patch fixes the
issue.

Fixes #15297
Fixes #15250
Add test for #10618 and #16382

Closes #10618
Closes #16382
libunicode: optimize char functions for ascii characters
core: Separate failure formatting in str methods slice, slice_to, slice_from

Use a separate inline-never function to format failure message for
str::slice() errors.

Using strcat's idea, this makes sure no formatting code from failure is
inlined when str::slice() is inlined. The number of `unreachable` being
inlined when usingi `.slice()` drops from 5 to just 1.
librustc: Don't ICE with type when name only contain underscores.
std: Use concat! and stringify! to simplify the most common assert! case.

With no custom message, we should just use concat! + stringify! for
`assert!(expr)`.

Inspired by issue #16625
Test case to illustate/reproduce bug.
Copy only up to `min(new_size, old_size)` when doing reallocate.

Fix #16687
extern crate foobar as foo;

Implements remaining part of RFC #47.
Addresses issue #16461.

Removed link_attrs from rust.md, they don't appear to be supported by
the parser.

Changed all the tests to use the new extern crate syntax

Change pretty printer to use 'as' syntax
auto merge of #16670 : Swatinem/rust/charascii, r=alexcrichton

I was doing a lot of parsing ascii strings, and the generic bsearch functions in `tables.rs` came up very high in the profile.
This should avoid calling those functions for simple ASCII range chars.
Log linker stderr and stdout.
auto merge of #16691 : klutzy/rust/issue-15297, r=alexcrichton

First commit fixes issue regarding recognizing MSYS2 build.
Second commit fixes issue regarding MSYS/Windows paths.
Enable the MergeFunc pass

Fixes #9536
auto merge of #16697 : Sawyer47/rust/new-test, r=huonw

Closes #10618
Closes #16382
doc: move misplaced comma

Also:

* Remove unseeming repetition.
* By now, the reader has already heard that Rust is safe by default, so
reduce the overlong sentence, making it easier to read.
auto merge of #16698 : bluss/rust/slice-bloat, r=huonw

These are somewhat stop-gap solutions to address #16625 

core: Separate failure formatting in str methods slice, slice_to, slice_from

Use a separate inline-never function to format failure message for
str::slice() errors.

Using strcat's idea, this makes sure no formatting code from failure is
inlined when str::slice() is inlined. The number of `unreachable` being
inlined when usingi `.slice()` drops from 5 to just 1.



The testcase:

```
#![crate_type = "lib"]
pub fn slice(x: &str, a: uint, b: uint) -> &str {
    x.slice(a, b)
}
```

shrinks from 16.9 kB to 3.3 kB llvm IR, and the number of `unreachable` drops from 5 to 1.
auto merge of #16703 : bluss/rust/assert-bloat, r=huonw

With no custom message, we should just use concat! + stringify! for
`assert!(expr)` to avoid the string formatting code path.

Inspired by issue #16625
lint: Improve camel case suggestion when empty.