Add a new feature to enable this, since `const extern fn`
support is unstable

Remove duplicate target

Add settimeofday for solaris/illumos

Closes #1547

Sort targets in documentation. Fixes #1524.

Should be a simple but effective fix for #1524. Assume `sort` command is available.

Should be a simple but effective fix for #1524. Assume `sort` command is available.

Refine definition of mcontext_t on x86_64-unknown-linux-musl

Fixes #1553

I've inlined the links I used for defining constants and fields, although they pretty much map to the changes introduced in ac7f0fac and ae06c2b2.

NetBSD pthread_attr_get_np

This patch adds a signature for the [`pthread_attr_get_np`](https://netbsd.gw.com/cgi-bin/man-cgi?pthread_attr_get_np+3+NetBSD-current) function for all architectures on NetBSD.

Closes #1538

Add networking and futex constants for uclibc

I needed this variables to run some rust program that uses `net2` on a embedded Linux platform.
This platform has as MIPS 74Kc CPU and uses uclibc.

"Proof" that this variables are the same under all uclibc targets:
<details>
  <summary>IP constants</summary>

  ```
➜  uClibc git:(master) git remote -v
origin	git@github.com:kraj/uClibc.git (fetch)
origin	git@github.com:kraj/uClibc.git (push)
➜  uClibc git:(master) git describe --tags
v0.9.33-984-gca1c74d67
➜  uClibc git:(master) rg -t h -i "define IPV6_MULTICAST_HOPS"
libc/sysdeps/linux/common/bits/in.h
142:#define IPV6_MULTICAST_HOPS	18
➜  uClibc git:(master) rg -t h -i "define IP_MULTICAST_IF"
libc/sysdeps/linux/common/bits/in.h
35:#define IP_MULTICAST_IF 32	/* in_addr; set/get IP multicast i/f */
➜  uClibc git:(master) rg -t h -i "define IPV6_MULTICAST_IF"
libc/sysdeps/linux/common/bits/in.h
141:#define IPV6_MULTICAST_IF	17
➜  uClibc git:(master) rg -t h -i "define IPV6_UNICAST_HOPS"
libc/sysdeps/linux/common/bits/in.h
140:#define IPV6_UNICAST_HOPS	16

  ```
</details>
<details>
  <summary>FUTEX_WAIT</summary>

  ```
➜  uClibc git:(master) rg -t h -i "define FUTEX_WAIT\W"
libpthread/nptl/sysdeps/unix/sysv/linux/mips/lowlevellock.h
29:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/sparc/lowlevellock.h
31:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/metag/lowlevellock.h
29:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/arc/lowlevellock.h
29:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/arm/lowlevellock.h
28:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
32:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
47:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/alpha/lowlevellock.h
29:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
46:#define FUTEX_WAIT		0

libpthread/nptl/sysdeps/unix/sysv/linux/sh/lowlevellock.h
29:#define FUTEX_WAIT		0

  ```
</details>
</details>
<details>
  <summary>FUTEX_PRIVATE_FLAG</summary>

  ```
➜  uClibc git:(master) rg -t h -i "define FUTEX_PRIVATE_FLAG\W"
libpthread/nptl/sysdeps/unix/sysv/linux/mips/lowlevellock.h
40:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/sparc/lowlevellock.h
42:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
43:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/sh/lowlevellock.h
38:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/metag/lowlevellock.h
40:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/arm/lowlevellock.h
39:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/alpha/lowlevellock.h
40:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/arc/lowlevellock.h
40:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
57:#define FUTEX_PRIVATE_FLAG	128

libpthread/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
58:#define FUTEX_PRIVATE_FLAG	128

  ```
</details>
<details>
  <summary>FUTEX_WAKE</summary>

  ```
➜  uClibc git:(master) rg -t h -i "define FUTEX_WAKE\W"
libpthread/nptl/sysdeps/unix/sysv/linux/mips/lowlevellock.h
30:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/metag/lowlevellock.h
30:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/arm/lowlevellock.h
29:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/powerpc/lowlevellock.h
33:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/sparc/lowlevellock.h
32:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/alpha/lowlevellock.h
30:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/sh/lowlevellock.h
30:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/arc/lowlevellock.h
30:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/x86_64/lowlevellock.h
47:#define FUTEX_WAKE		1

libpthread/nptl/sysdeps/unix/sysv/linux/i386/lowlevellock.h
48:#define FUTEX_WAKE		1

  ```
</details>

Add settimeofday for openbsd

Closes #1546

Add `RLIM_INFINITY` definition for Android

This adds the definition for `RLIM_INFINITY` to Android, mirroring the Linux definition. Ran into this while trying to build `sccache` natively in Termux on Android, and is the only thing preventing `sccache` from building on libc master.

Add IFLA_INFO_ consts

See https://github.com/torvalds/linux/blob/54ecb8f7/include/uapi/linux/if_link.h#L354-L362

Support vxWorks in libc-test

r? @gnzlbg

Use minimal profile for rustup

Haven't tested it but should fix issue from https://github.com/rust-lang/libc/pull/1549#issuecomment-542203074

Haiku: Fix constants for S_IFIFO and S_IFCHR

Some updates for vxWorks

adding FIOGETNAME which is used by ioctl() to get file path
adding PATH_MAX
use type c_int for _PARM_NAME_MAX and _PARM_PATH_MAX

adding PATH_MAX

use type c_int for _PARM_NAME_MAX and _PARM_PATH_MAX

See
https://github.com/torvalds/linux/blob/54ecb8f7/include/uapi/linux/if_link.h#L354-L362

sync with rust-lang/libc master

Add `pthread_main_np` to FreeBSD-like and `_lwp_self` to NetBSD

Sync to rust-lang/libc master

update rtpSpawn prototype