The mx_handle_wait_* syscalls in Magenta were renamed to
mx_object_wait. The syscall is used in the Magenta/Fuchsia
implementation of std::process, to wait on child processes.

In addition, this patch enables the use of the system provided
libbacktrace library on Fuchsia targets. Symbolization is not yet
working, but at least it allows printing hex addresses in a backtrace
and makes building succeed when the backtrace feature is not disabled.

So I just encountered this error for the first time. It's unclear what
it means, why I encountered it, or how to fix it. But worst of all, it
has a random newline and weird indentation! This commit fixes that last
bit.

The readdir_r function is deprecated on newer Posix systems because of
various problems, and not implemented at all for Fuchsia. There are
already implementations using both, and this patch switches Fuchsia
over to the readdir-based one.

Fixes rust-lang#40021 for Fuchsia, but that issue also contains discussion of
what should happen for other Posix systems.

Update the implementation of name_bytes to use the owned string (which
is thread safe). Also bump the src/liblibc submodule now that's merged.

…e-path, r=alexcrichton

Set rustdoc --test files' path relative to the current directory

r? @alexcrichton

…tsakis

Normalize labeled and unlabeled breaks

Part of rust-lang#39849.

Additional docs for Vec, String, and slice trait impls

r? @steveklabnik

Fix test caching on Windows/GNU

Addresses rust-lang#36385 (comment)

Previously the sysroot directory was purged on every build and mingw startup objects were rebuilt unconditionally and always triggered test reruns.
Now the sysroot directory is reused and mingw startup objects are rebuilt only when necessary, so test caching works.

…chton

Follow rename of mx_handle_wait Magenta syscalls

The mx_handle_wait_* syscalls in Magenta were renamed to
mx_object_wait. The syscall is used in the Magenta/Fuchsia
implementation of std::process, to wait on child processes.

In addition, this patch enables the use of the system provided
libbacktrace library on Fuchsia targets. Symbolization is not yet
working, but at least it allows printing hex addresses in a backtrace
and makes building succeed when the backtrace feature is not disabled.

Fix indentation of error message

So I just encountered this error for the first time. It's unclear what
it means, why I encountered it, or how to fix it. But worst of all, it
has a random newline and weird indentation! This commit fixes that last
bit.

<img width="680" alt="screen shot 2017-02-18 at 4 35 36 pm" src="https://cloud.githubusercontent.com/assets/1529387/23097087/0ef5ac4a-f5f9-11e6-9132-18ce759f7092.png">

Simplify/fix adaptive hashmap

Please see rust-lang#38368 (comment) for context.

The shift length math is broken. It turns out that checking for the shift length is complicated. Using simulations it's possible to see that a value of 2000 will only get probabilities down to ~1e-7 when the hashmap load factor is 90% (rust goes up to 90.9% as of today). That's probably not good enough to go into the stdlib with pluggable hashers.

So this PR simplify the adaptive behavior to only consider displacement, which is much safer and very useful by itself.

There's two comments because one of them is already being tested to be merged by bors.

…sxcv

Add missing urls and examples into Barrier structs

r? @frewsxcv

Switch Fuchsia to readdir (instead of readdir_r)

The readdir_r function is deprecated on newer Posix systems because of
various problems, and not implemented at all for Fuchsia. There are
already implementations using both, and this patch switches Fuchsia
over to the readdir-based one.

Fixes rust-lang#40021 for Fuchsia, but that issue also contains discussion of
what should happen for other Posix systems.

Clarify thread::Builder::stack_size docs

Add two pieces of information:

* the size is in bytes
* the actual stack size might be bigger.

Also change the example to use a more realistic value of 32 kilobytes.

r? @steveklabnik