Rebase of #610 and also move emscripten up much higher in the hierarchy to
ensure that it doesn't have too much of a ripple effect on other platforms.

This involved moving down a good number of definitions, but hopefully was done
with care to not break anything!

haiku: Add missing signals

* Now a complete signal list on Haiku minus reserved.
* Fixes build failure due to missing SIGUSR1

* Now a complete signal list on Haiku minus reserved.
* Fixes build failure due to missing SIGUSR1

Add {,f}stat{,v}fs64 API bindings

Closes https://github.com/rust-lang/libc/issues/738

haiku: Correct typo

Add more fcntl and seal constants for Android/Linux

Add more fcntl constants for android

This works by specifying a "runner" for actually executing the binary.
This doesn't apply to the Android or NetBSD runs because there
isn't a simple binary that just runs the executable.

We now create an additional binary `linux_fcntl` for testing this
since there are header conflicts when including all necessary headers.
This binary is run on all platforms even though it's empty on all non-
Android/non-Linux platforms.

Testing has been switched from a custom binary to using a runner-less
test (or pair of tests). This means that for local development a simple
`cd libc-test && cargo test` will run all the tests. CI has also been
updated here to reflect that.

Fix spelling of ptrace's request argument

Couldn't handle seeing this anymore after working on a ptrace API for `nix`!

L4Re improvements

This commit improves the x86_64 uClibc port and splits of L4Re-specific structs into a separate submodule. It defines additional constants and fixes some unfinished structs.

Remove OpenBSD CI

It's now broken due to changes in the `gcc` crate and having a too-old compiler,
and in general it's unfortunately architecturally so different from the other
test frameworks that it's difficult to maintain over time.

It's now broken due to changes in the `gcc` crate and having a too-old compiler,
and in general it's unfortunately architecturally so different from the other
test frameworks that it's difficult to maintain over time.

Remove fexecvpe from Haiku and MacOS/IOS where it's not implemented

I was going to remove the skip-check from `build.rs` to see if we might be able to enable the function check on at least some platforms, but I'll assume it doesn't work on any as has been suggested.

Closes #732.

It's not supported on those platforms

*   correct sigaction
*   correct stat, alias stat64
*   remove doubled statvfs definition

Openbsd kqueue

The PR supersede #613 to add exception on the testsuite.

they will be released with OpenBSD 6.2

OpenBSDs kqueue now has EV_RECEIPT and EV_DISPATCH.

I wrote a patch and the devs merged it into current:
https://marc.info/?l=openbsd-tech&m=149621427511219&w=2

This change extends the rust libc crate to provide the feature.

skip siginfo_t.si_addr type check on OpenBSD

the type changed from *c_char to *c_void in 6.1

the type changed from *c_char to *c_void in 6.1

Add getgrouplist(), add initgroups() to BSD platforms