rustc: Use rust strings for failure arguments

This avoids having to perform conversions from `*u8` to `&'static str` which can
suck in a good deal of code.

Closes #14442
Use clang++ for CXX when --enable-clang.

Signed-off-by: OGINO Masanori <masanori.ogino@gmail.com>
std: change select! docs from 'ports' to 'receivers'
fix MIPS target
Fixed deprecation warning text for mem::move_val_init and its associated comment.
rust manual: supertraits seperator is wrong
rustc: clarify warning about native deps for a staticlib.

This adjusts the "unlinked native library" warning one receives when
compiling with `crate_type="staticlib"`. The warning is just trying to
tell the user that they need to link against these libraries, but the
old text wasn't making this obvious; the new text says this explicitly.
mk: Don't build any docs with --disable-docs.
native: Ignore stdio fds with /dev/null

When spawning a process, stdio file descriptors can be configured to be ignored,
which basically means that they'll be closed. Currently this is done by
literally closing the file descriptors in the child, but this can have adverse
side effects if the child process then opens a new file descriptor, assigning it
to a stdio number.

To work around the problems of the child, this commit alters the process
spawning code to map stdio fds to /dev/null on unix (and a similar equivalent on
windows) when they are specified as being ignored. This should allow spawned
programs to have more expected behavior when opening new files.

Closes #14456
rustdoc: Only link to local inlined foreign items

This commit alters rustdoc to keep a hash set of known inlined items which is a
whitelist for generating URLs to.

Closes #14438
Move std::{reflect,repr,Poly} to a libdebug crate

This commit moves reflection (as well as the {:?} format modifier) to a new
libdebug crate, all of which is marked experimental.

This is a breaking change because it now requires the debug crate to be
explicitly linked if the :? format qualifier is used. This means that any code
using this feature will have to add `extern crate debug;` to the top of the
crate. Any code relying on reflection will also need to do this.

Closes #12019

[breaking-change]
auto merge of #14364 : alexcrichton/rust/libdebug, r=brson

This commit moves reflection (as well as the {:?} format modifier) to a new
libdebug crate, all of which is marked experimental.

This is a breaking change because it now requires the debug crate to be
explicitly linked if the :? format qualifier is used. This means that any code
using this feature will have to add `extern crate debug;` to the top of the
crate. Any code relying on reflection will also need to do this.

Closes #12019

[breaking-change]
Rename PatUniq to PatBox. Fixes part of #13910.
auto merge of #14452 : alexcrichton/rust/issue-14438, r=huonw

This commit alters rustdoc to keep a hash set of known inlined items which is a
whitelist for generating URLs to.

Closes #14438
configure: Move clang's libcpp out into flag
configure: Only use -m32 on x86-* 32 bit systems
configure: setup triples on hf arm platforms
auto merge of #14454 : omasanori/rust/cfg_cxx, r=alexcrichton
Rename UTF16Item[s] to Utf16Item[s]

According to Rust's style guide acronyms should be CamelCase.

[breaking-change]
auto merge of #14455 : crabtw/rust/mips, r=alexcrichton

Because IPv4 address conversion doesn't consider big-endian target, I add functions to handle that.
These function names may need to be changed, but I can't come up with a good one.