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.

Add truncate(2) to Unix platforms

Add acct(2) to BSD module

The `acct` syscall is supported on BSD platforms, the PR aims to add it to the BSD module.

This patch removes the x86_64-rumprun-netbsd triple from Travis CI.

Arch specific ptrace commands for BSDs

This PR is to add architecture specific ptrace requests etc.

Don't merge this yet if it passes I want to go over the other BSDs and architectures to see if I've missed anything I'm just creating the PR to get that initial CI approval that it's right as I expect this bit to be more fiddly.

Add ptrace for non-apple BSDs

So yesterday I did a PR for ptrace for apple, I've now gone through the ptrace header files for the other BSDs supported by libc and added ptrace + constants for all of them.

Given the lack of ptrace in any of them I don't know if the test has to be changed at all for the new functions so I'll tackle any CI errors that come up if and as they appear.

* Added ptrace and constants for all freebsdlike and netbsdlike OSs

Added ptrace constants for apple

I noticed the ptrace constants were missing for apple so I've added them referencing this [header](https://opensource.apple.com/source/xnu/xnu-792.13.8/bsd/sys/ptrace.h). This doesn't add any new functions just constants so I haven't added any tests which seems to be correct.

Revisit work on cvoid

At the recommendation of @SimonSapin [here](https://github.com/rust-lang/rust/issues/53856#issuecomment-422932721), I have revisited the build script to check whether `core::ffi::c_void` resolves, instead of relying on a particular `rustc` version. This allows use on `1.30.x` builds with `core::ffi::c_void`.

I also noticed that `c_void` is defined twice in this crate, once in `lib.rs` and again in `switch.rs`. This instead defines `c_void` for every target except `wasm32`. As far as I can tell, this shouldn't actually change functionality on any existing targets.

Add ftok on MacOS

Provide a symbol for the `ftok` function declared in sys/ipc.h, for completeness and to allow calling `ftok` to generate the key value for `shmat`.

Add fcntl constants for advisory locking on BSDs

For range-based locking POSIX fcntl locks are needed. This adds the
constants F_RDLCK, F_UNLCK, and F_WRLCK for FreeBSD, NetBSD, OpenBSD,
DragonFlyBSD, and macOS/iOS. Fortunately these values are defined the same across these platforms.

Provide a symbol for the `ftok` function declared in sys/ipc.h, for completeness and to allow calling `ftok` to generate the key value for `shmat`.

For range-based locking POSIX fcntl locks are needed. This adds the
constants F_RDLCK, F_UNLCK, and F_WRLCK for FreeBSD, NetBSD, OpenBSD,
DragonFlyBSD, and macOS/iOS. Fortunately these values are defined the same across these platforms.

Expose futimens and utimensat on FreeBSD and DragonFly

Should have sent this out with #1084 but I didn't notice then that these were missing (see https://github.com/nix-rust/nix/pull/944).

Haven't been able to test these locally as I do not have access to these platforms. Will rely on CI to verify these for me.

Expose futimens and utimensat on Apple platforms

Entries copy/pasted from `netbsdlike/mod.rs`.