Disable generating split-stack code

Allows to compile for archs which do not have (or have limited)
segmented stack support like embedded.
Basic iOS support
Better dylib skipping based on Alex Crichton code
auto merge of #14811 : forticulous/rust/refcell-show, r=alexcrichton

Show impl for RefCell and friends
Relicense shootout-pidigits.rs

Everyone agreed.

Related to #14248, close #14718
auto merge of #14813 : cmr/rust/once-docs-unsafe, r=alexcrichton
Relicense shootout-binarytrees.rs

Everyone agreed.

Related to #14248, close #14720
travis: Don't use a local jemalloc

Turns out they don't have the `je_` prefix, so we can't use the system-installed
jemalloc.
auto merge of #14816 : theptrk/rust/unclear-comment, r=huonw

The old comment left it unclear if this is creating a random value or doing a check as to whether or not the generator is available or some other operation.

See: http://stackoverflow.com/questions/24153311/when-is-rng-gen-not-true
auto merge of #14819 : michaelwoerister/rust/unique_type_id, r=alexcrichton

With this change, rustc creates a unique type identifier for types in debuginfo. These type identifiers are used by LLVM to correctly handle link-time-optimization scenarios but also help rustc with dealing with inlining from other crates. For more information, see the documentation block at the top of librustc/middle/trans/debuginfo.rs and also [my blog post about the topic](http://michaelwoerister.github.io/2014/06/05/rust-debuginfo-and-unique-type-identifiers.html). This should fix the LTO issues that have been popping up lately. 

The changes to the debuginfo module's inner workings are also improved by this. Metadata uniquing of pointer types is not handled explicitly instead of relying on LLVM doing the right thing behind the scenes, and region parameters on types should not lead to metadata duplication anymore.

There are two things that I'd like to get some feedback on:
1. IDs for named items consist of two parts: The [Strict Version Hash](https://github.com/mozilla/rust/blob/0.10/src/librustc/back/svh.rs#L11) of their defining crate and the AST node id of their definition within that crate. My question is: Is the SVH a good choice for identifying the crate? Is it even going to stay? The [crate-id RFC](https://github.com/rust-lang/rfcs/pull/109) got me confused.
2. Unique Type Identifiers can be arbitrary strings and right now the format is rather verbose. For debugging this is nice, because one can infer a lot about a type from the type id alone (it's more or less a signature). For deeply nested generics, id strings could get rather long though. One option to limit the id size would be to use some hashcode instead of the full id (anything that avoids collision as much as possible). Another option would be to use a more compact representation, like ty_encode. This reduces size but also readability.
Since these ID's only show up in LLVM IR, I'm inclined to just leave in the verbose format for now, and only act if sizes of rlibs become a problem.
auto merge of #14858 : alexcrichton/rust/no-jemalloc-on-travis, r=thestinger

Turns out they don't have the `je_` prefix, so we can't use the system-installed
jemalloc.
Cosmetic fixes & comments
added get_mut() for [T]
There should be no metadata to read on iOS
Dump results of analysis phase as CSV

Adds the option -Zsave-analysis which will dump the results of syntax and type checking into CSV files. These can be interpreted by tools such as DXR to provide semantic information about Rust programs for code search, cross-reference, etc.

Authored by Nick Cameron and Peter Elmers (@pelmers; including enums, type parameters/generics).
auto merge of #13222 : nick29581/rust/dxr4, r=brson

Adds a -Z flag `save-analysis` which runs after the analysis phase of the compiler and saves a bunch of info into a CSV file for the crate. This is designed to work with the DXR code browser, but is frontend-independent, that is this info should be useful for all kinds of code browsers, IDEs, or other tools.

I need to squash commits before landing (there will probably be a fair few to come), please ignore them for now and just comment on the changes.
auto merge of #14831 : alexcrichton/rust/format-intl, r=brson

* The select/plural methods from format strings are removed
* The # character no longer needs to be escaped
* The \-based escapes have been removed
* '{{' is now an escape for '{'
* '}}' is now an escape for '}'

Closes #14810
[breaking-change]
Add Bitwise::{swap_bytes, rotate_left, rotate_right} methods
Introduce VecPerParamSpace and use it to represent sets of types and
parameters

This involves numerous substeps:

1. Treat Self same as any other parameter.
2. No longer compute offsets for method parameters.
3. Store all generic types (both trait/impl and method) with a method,
   eliminating odd discrepancies.
4. Stop doing unspeakable things to static methods and instead just use
   the natural types, now that we can easily add the type parameters from
   trait into the method's polytype.
5. No doubt some more. It was hard to separate these into distinct commits.

Fixes #13564
librustc: Forbid enum-to-float casts.

Closes #14794.

If you're casting from an enum to a float, cast through an integer
first.

[breaking-change]