These aren't exposed on non-MIPS musl targets, but since they're
part of a kernel API, they're still applicable, so we just don't
test them there but expose them anyways.

Note that termios2 doesn't exist on powerpc(64), termios
is used instead.

* Add syscall tables to most remaining arches in `src/unix/notbsd`
* Add aarch64/arm musl to CI
* Update dependencies

pthread_cancel() is safer way to terminate thread than pthread_kill().

This function can be found from ISO/IEC 9945-1:1996 (“POSIX.1”) and
first introduced into Single Unix Specification version 2 on 1997.

powerpc64 was missing in musl/mod.rs and making build fail
as it was not able to find types, like c_char.

Motivation: there is no glibc wrapper for this syscall

Signed-off-by: Tom Kirchner <tjk@amazon.com>
Signed-off-by: Ben Cressey <bcressey@amazon.com>

Also remove unneeded platform gating

This change adds the Linux-specific timerfd API to libc.

This code appears to be modeled on the macros in glibc bits/sysmacros.h
(since Glibc 2.26). Fix the masking of bits for minor() to match that
implementation, which also corresponds with the explanatory comment in
that file.

For some reason the type of ptrace request constants in musl change for the register based requests. As they are used in the same way and this doesn't mimic musl this has been changed for consistency and ease of use.

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!