solarish: define IP_BOUND_IF and IPV6_BOUND_IF

# Description

These socket options are currently defined only on macOS and friends,
but they exist on illumos and Solaris as well.

This commit defines these socket options on solarish operating systems.

# Sources

On Solaris, see the man page [`ip(7P)`].

I'd like to provide a link to the illumos manual pages, but apparently
https://illumos.org/man seems to be impacted by today's AWS outage.

The constants are defined in `/usr/include/netinet/in.h`:

```console
eliza@atrium ~ $ uname -a
SunOS atrium 5.11 helios-2.0.22827 i86pc i386 i86pc
eliza@atrium ~ $ rg 'IP(V6)?_BOUND_IF' /usr/include
/usr/include/netinet/in.h
978:#define   IP_BOUND_IF                0x41    /* bind socket to an ifindex       */
1311:#define  IPV6_BOUND_IF              0x41    /* bind to an ifindex */
```

[`ip(7P)`]: https://docs.oracle.com/cd/E86824_01/html/E54777/ip-7p.html

# Checklist

- [x] Relevant tests in `libc-test/semver` have been updated
- [x] No placeholder or unstable values like `*LAST` or `*MAX` are
  included (see [#3131](#3131))
- [x] Tested locally (`cd libc-test && cargo test --target mytarget`);
  especially relevant for platforms that may not be checked in CI

Author: hawkw

libc-test/semver/solarish.txt

@@ -1,10 +1,12 @@
 AIO_ALLDONE
 AIO_CANCELED
 AIO_NOTCANCELED
+IPV6_BOUND_IF
 IPV6_DONTFRAG
 IPV6_PKTINFO
 IPV6_RECVTCLASS
 IPV6_TCLASS
+IP_BOUND_IF
 IP_DONTFRAG
 IP_PKTINFO
 IP_TOS

src/unix/solarish/mod.rs

@@ -1148,6 +1148,7 @@ pub const IPV6_DONTFRAG: c_int = 0x21;
 pub const IPV6_SEC_OPT: c_int = 0x22;
 pub const IPV6_TCLASS: c_int = 0x26;
 pub const IPV6_V6ONLY: c_int = 0x27;
+pub const IPV6_BOUND_IF: c_int = 0x41;
 
 cfg_if! {
     if #[cfg(target_pointer_width = "64")] {
@@ -1691,6 +1692,7 @@ pub const IP_ADD_SOURCE_MEMBERSHIP: c_int = 23;
 pub const IP_DROP_SOURCE_MEMBERSHIP: c_int = 24;
 pub const IP_BLOCK_SOURCE: c_int = 21;
 pub const IP_UNBLOCK_SOURCE: c_int = 22;
+pub const IP_BOUND_IF: c_int = 0x41;
 
 // These TCP socket options are common between illumos and Solaris, while higher
 // numbers have generally diverged: