Introduced a chapter that describes how to perform callbacks from C to Rust
Further details on channel idea
Update guide-ffi.md

Simplified the first examples to demonstrate callbacks without other threads involved and shortened the elaboration about async callbacks.
document file!
Fix documentation typos
Scan the entire crate for exported macros

It previously missed anything in an inner module.
Disabled the tests for the new code blocks
Don't emit landing pads with -Z no-landing-pads

Closes #11647
rustuv: Re-work sockaddr glue to not use malloc

This means we can purge even more C from src/rt!
auto merge of #11636 : alexcrichton/rust/purge-all-the-c, r=brson

This means we can purge even more C from src/rt!
Fix a pathological const checking case

The included test case would essentially never finish compiling without this
patch. It recursies twice at every ExprParen meaning that the branching factor
is 2^n

The included test case will take so long to parse on the old compiler that it'll
surely never let this crop up again.
Fix cross-compiled pretty tests

They need to read the metadata of cross-compiled crates, so the pretty things
need to have the right target.
auto merge of #11675 : alexcrichton/rust/fix-snap, r=cmr

They need to read the metadata of cross-compiled crates, so the pretty things
need to have the right target.
auto merge of #11653 : alexcrichton/rust/issue-11647, r=luqmana

Closes #11647
auto merge of #11486 : Matthias247/rust/doc, r=cmr

I wrote a chapter for the FFI tutorial that describes how to perform callbacks from C code to Rust and gives some hints about what to consider and synchronization.

I just needed that for my own wrapper and thought it would be helpful for others.
Register new snapshots

Upgrade the version to 0.10-pre
auto merge of #11662 : alexcrichton/rust/faster-parens, r=huonw

The included test case would essentially never finish compiling without this
patch. It recursies twice at every ExprParen meaning that the branching factor
is 2^n

The included test case will take so long to parse on the old compiler that it'll
surely never let this crop up again.
auto merge of #11674 : indirect/rust/doc_file, r=alexcrichton

Found out about `file!` today from o11c in IRC.
auto merge of #11684 : FlaPer87/rust/doc_typos, r=cmr
auto merge of #11687 : sfackler/rust/macro-export-inner-crate, r=alexcrichton

It previously missed anything in an inner module.