NetBSD: these extattr functions are not in libutil, but libc

 - extattr_namespace_to_string()
 - extattr_string_to_namespace()

Add F_RDLCK/F_WRLCK/F_UNLCK to several platforms

These are used by the flock wrapper in rustc_data_structures. The constants were already present in x86_64-linux-gnu and BSD (since 4928bd98).

Currently the `flock` wrapper in `rustc_data_structures` does not work on several 32-bit musl targets, because they expect the `LARGEFILE64` version of the `F_SETLK`/`F_SETLKW` constants. This PR is a prerequisite to converting that code to use the `libc` types and constants, instead of (inaccurately) duplicating them, since `libc` already provides architecture-specific definitions of the relevant constants.

 - extattr_namespace_to_string()
 - extattr_string_to_namespace()

These are used by the flock wrapper in rustc_data_structures. The
constants were already present in x86_64-linux-gnu and BSD (since
4928bd98).

NetBSD: fix extattr_set_* return types

On FreeBSD and Dragonfly, don't unnecessarily link to libutil

Also, alphabetize this section, since I'm merging two sections anyway.

Fixes #1113

NetBSD: fix pthread types on arm and powerpc

Bump ctest from 0.2.4 to 0.2.6

Bumps [ctest](https://github.com/alexcrichton/ctest) from 0.2.4 to 0.2.6.
- [Release notes](https://github.com/alexcrichton/ctest/releases)
- [Commits](https://github.com/alexcrichton/ctest/commits

)

Signed-off-by: dependabot[bot] <support@dependabot.com>

Also, alphabetize this section, since I'm merging two sections anyway.

Fixes #1113

Add extattr(2) and extattr(3) definitions for FreeBSD and NetBSD

DragonflyBSD does define 3 of these 14 functions.  But I elected not to
add it to the PR because I can't find any evidence that these syscalls
are used on Dragonfly, even in the base system.  And by themselves,
those three are insufficient for the xattr crate.

This bug was never diagnosed.  Perhaps it's been resolved by a newer
compiler.
Fixes #856

DragonflyBSD does define 3 of these 14 functions.  But I elected not to
add it to the PR because I can't find any evidence that these syscalls
are used on Dragonfly, even in the base system.  And by themselves,
those three are insufficient for the xattr crate.

Add CMSG macros for unix/bsd and unix/notbsd

This adds the ["Ancillary Data Object Macros" from RFC 2292](https://tools.ietf.org/html/rfc2292#section-4.3). My C's weak but I think I've translated them faithfully. Tested on macOS and Linux/glibc.

update osx builds to xcode10

remove the iOS simulator targets from CI / update ctest

Also while here: fix powerpc64, mips, and mips64 pthread types.  These
targets are not yet fully/correctly implemented in rust-libc however.

exclude CI files from crates.io

Finish correcting ioctl(2) interfaces on musl/ppc64

Last commit fixed the function definition but not the constants.  Oops.

Last commit fixed the function definition but not the constants.  Oops.

update ctest version

Added dup3() support on FreeBSD, NetBSD, OpenBSD and Solaris

Added `dup3()` support on FreeBSD, NetBSD, OpenBSD and Solaris.

The `dup3()` API is present in:
- FreeBSD 10.0 an later.
- NetBSD 6.0 and later.
- OpenBSD 5.7 and later.
- Solaris 11.4 and later.

Correct ioctl(2) interface definition for musl/ppc64

Add TIOCGRS485 and TIOCSRS485 for musl #1094

I need help with adding `TIOCSRS485` and `TIOCSRS485` constants to libc.