typestrong const integers

~~It would be great if someone could run crater on this PR, as this has a high danger of breaking valid code~~ Crater ran. Good to go.

----

So this PR does a few things:

1. ~~const eval array values when const evaluating an array expression~~
2. ~~const eval repeat value when const evaluating a repeat expression~~
3. ~~const eval all struct and tuple fields when evaluating a struct/tuple expression~~
4. remove the `ConstVal::Int` and `ConstVal::Uint` variants and replace them with a single enum (`ConstInt`) which has variants for all integral types
  * `usize`/`isize` are also enums with variants for 32 and 64 bit. At creation and various usage steps there are assertions in place checking if the target bitwidth matches with the chosen enum variant
5. enum discriminants (`ty::Disr`) are now `ConstInt`
6. trans has its own `Disr` type now (newtype around `u64`)

This obviously can't be done without breaking changes (the ones that are noticable in stable)
We could probably write lints that find those situations and error on it for a cycle or two. But then again, those situations are rare and really bugs imo anyway:

```rust
let v10 = 10 as i8;
let v4 = 4 as isize;
assert_eq!(v10 << v4 as usize, 160 as i8);
 ```

stops compiling because 160 is not a valid i8

```rust
struct S<T, S> {
    a: T,
    b: u8,
    c: S
}
let s = S { a: 0xff_ff_ff_ffu32, b: 1, c: 0xaa_aa_aa_aa as i32 };
```

stops compiling because `0xaa_aa_aa_aa` is not a valid i32

----

cc @EddyB @pnkfelix

related: https://github.com/rust-lang/rfcs/issues/1071

Fix LLVM assert with write_volatile

Fixes #29663

Give a more accurate error on thin-to-fat ptr cast

Fixes #31511

Define AVX compare and blend intrinsics

This defines the following intrinsics:

 * `_mm256_blendv_pd`
 * `_mm256_blendv_ps`
 * `_mm256_cmp_pd`
 * `_mm256_cmp_ps`

I verified these locally.

Fix. FreeBSD snapshot

Previous snapshot was complied with avx2 instructions by accident.

Actual file: http://people.freebsd.org/~davide/rust/rust-stage0-2016-02-17-4d3eebf-freebsd-x86_64-f38991fbb81c1cd8d0bbda396f98f13a55b42804.tar.bz2

/cc @alexcrichton @dcci

Reject unspecified IP from global

Also fixed the test

Fix import resolution bug

This fixes #32222, which was introduced in #31726.

Fixup stout/stderr on Windows

WriteConsoleW can fail if called with a large buffer so we need to slice
any stdout/stderr output.
However the current slicing has a few problems:
 1. It slices by byte but still expects valid UTF-8.
 2. The slicing happens even when not outputting to a console.
 3. panic! output is not sliced.

This fixes these issues by moving the slice to right before
WriteConsoleW and slicing on a char boundary.

Fixes #31511

Rollup of 4 pull requests

- Successful merges: #32164, #32179, #32212, #32218
- Failed merges:

The exact command used was:

    $ cd src/etc/platform-intrinsics/x86
    $ python2 ../generator.py --format compiler-defs -i info.json   \
      sse.json sse2.json sse3.json ssse3.json sse41.json sse42.json \
      avx.json avx2.json fma.json                                   \
      > ../../../librustc_platform_intrinsics/x86.rs

This defines the `_mm256_blendv_pd` and `_mm256_blendv_ps` intrinsics.
The `_mm256_blend_pd` and `_mm256_blend_ps` intrinsics are not available
as LLVM intrinsics. In Clang they are implemented using the
shufflevector builtin.

Intel reference: https://software.intel.com/en-us/node/524070.

This defines `_mm256_cmp_pd` and `_mm256_cmp_ps`.

Intel reference: https://software.intel.com/en-us/node/524075.

Fix minor typos in doc.rust-lang.org/book

I've made a few typo and grammar fixes as I've been working through the book.

Don't allow values for codegen-units less than 1

r? @EddyB

fixes #32191

Removed integer suffixes in libsyntax crate

Do not report errors from regionck if other errors were already reported

Do not report errors from regionck if other errors were already reported during the lifetime of this inferencer. Fixes #30580.

r? @arielb1

Add Pass manager for MIR

A new PR, since rebasing the original one (https://github.com/rust-lang/rust/pull/31448) properly was a pain. Since then there has been several changes most notable of which:

1. Removed the pretty-printing with `#[rustc_mir(graphviz/pretty)]`, mostly because we now have `--unpretty=mir`, IMHO that’s the direction we should expand this functionality into;
2. Reverted the infercx change done for typeck, because typeck can make an infercx for itself by being a `MirMapPass`

r? @nikomatsakis

`NameResolution::decrement_outstanding_references`.

Call str::to_owned in String::from and uninline it

Call str::to_owned in String::from and uninline it

These methods were already effectively equal, but now one calls
the other, and neither is marked inline.
String::from does not need to be inlined, it can be without it just like
str::to_owned and String::clone are.

Fixes #32163

String::from does not need to be inlined, it can be without it just like
str::to_owned and String::clone are.

Previous snapshot was complied with avx2 instructions by accident.

Actual file: http://people.freebsd.org/~davide/rust/rust-stage0-2016-02-17-4d3eebf-freebsd-x86_64-f38991fbb81c1cd8d0bbda396f98f13a55b42804.tar.bz2

Fix name resolution in lexical scopes

Currently, `resolve_item_in_lexical_scope` does not check the "ribs" (type parameters and local variables). This can allow items that should be shadowed by type parameters to be named.

For example,
```rust
struct T { i: i32 }
fn f<T>() {
    let t = T { i: 0 }; // This use of `T` resolves to the struct, not the type parameter
}

mod Foo {
    pub fn f() {}
}
fn g<Foo>() {
    Foo::f(); // This use of `Foo` resolves to the module, not the type parameter
}
```

This PR changes `resolve_item_in_lexical_scope` so that it fails when the item is shadowed by a rib (fixes #32120).
This is a [breaking-change], but it looks unlikely to cause breakage in practice.

r? @nikomatsakis

mk: Fix `make dist`

With the movement of the erro-index-generator and rustbook, need to update the
rules in `make dist`.

Add AVX broadcast and conversion intrinsics

This adds the following intrinsics:

 * `_mm256_broadcast_pd`
 * `_mm256_broadcast_ps`
 * `_mm256_cvtepi32_pd`
 * `_mm256_cvtepi32_ps`
 * `_mm256_cvtpd_epi32`
 * `_mm256_cvtpd_ps`
 * `_mm256_cvtps_epi32`
 * `_mm256_cvtps_pd`
 * `_mm256_cvttpd_epi32`
 * `_mm256_cvttps_epi32`

The "avx" codegen feature must be enabled to use these.

std: Fix tracking issues and clean deprecated APIs

This PR fixes up a number of discrepancies found with tracking issues (some closed, some needed new ones, etc), and also cleans out all pre-1.8 deprecated APIs. The big beast here was dealing with `std::dynamic_lib`, and via many applications of a large hammer it's now out of the standard library.

Removes all unstable and deprecated APIs prior to the 1.8 release. All APIs that
are deprecated in the 1.8 release are sticking around for the rest of this
cycle.

Some notable changes are:

* The `dynamic_lib` module was moved into `rustc_back` as the compiler still
  relies on a few bits and pieces.
* The `DebugTuple` formatter now special-cases an empty struct name with only
  one field to append a trailing comma.

With the movement of the erro-index-generator and rustbook, need to update the
rules in `make dist`.

Statically link run-pass/command-before-exec so it passes not just whenever we happen to bootstrap perfectly.

Also change output for --unpretty mir to output function names in a prettier way.