Define SO_BINDTOIFINDEX on Fuchsia

Fuchsia supports SO_BINDTOIFINDEX as of API level 20:
https://cs.opensource.google/fuchsia/fuchsia/+/main:sdk/lib/zxio/socket.cc;l=755;drc=b03121152bf13fb8898a95b58d952c95ee73cd0c

(backport <#3784>)
(cherry picked from commit 09b8a4f)

Author: ewilden

libc-test/semver/fuchsia.txt

@@ -951,6 +951,7 @@ SOL_UDP
 SOL_X25
 SOMAXCONN
 SO_BINDTODEVICE
+SO_BINDTOIFINDEX
 SO_BSDCOMPAT
 SO_BUSY_POLL
 SO_DOMAIN

src/fuchsia/mod.rs

@@ -2981,6 +2981,7 @@ pub const SO_MARK: ::c_int = 36;
 pub const SO_RXQ_OVFL: ::c_int = 40;
 pub const SO_PEEK_OFF: ::c_int = 42;
 pub const SO_BUSY_POLL: ::c_int = 46;
+pub const SO_BINDTOIFINDEX: ::c_int = 62;
 
 pub const __SIZEOF_PTHREAD_RWLOCK_T: usize = 56;
 pub const __SIZEOF_PTHREAD_MUTEX_T: usize = 40;