Auto merge of #2762 - m-ou-se:netbsd-futex-consts, r=Amanieu

Add NetBSD's FUTEX_* constants.

This adds the FUTEX_* constants from NetBSD's [src/sys/sys/futex.h](http://ftp.netbsd.org/pub/NetBSD/NetBSD-current/src/sys/sys/futex.h).

libc-test/semver/netbsd.txt

@@ -346,6 +346,28 @@ FIONWRITE
 FIOSETOWN
 FLUSHO
 FOPEN_MAX
+FUTEX_WAIT
+FUTEX_WAKE
+FUTEX_FD
+FUTEX_REQUEUE
+FUTEX_CMP_REQUEUE
+FUTEX_WAKE_OP
+FUTEX_LOCK_PI
+FUTEX_UNLOCK_PI
+FUTEX_TRYLOCK_PI
+FUTEX_WAIT_BITSET
+FUTEX_WAKE_BITSET
+FUTEX_WAIT_REQUEUE_PI
+FUTEX_CMP_REQUEUE_PI
+FUTEX_PRIVATE_FLAG
+FUTEX_CLOCK_REALTIME
+FUTEX_CMD_MASK
+FUTEX_WAITERS
+FUTEX_OWNER_DIED
+FUTEX_SYNCOBJ_1
+FUTEX_SYNCOBJ_0
+FUTEX_TID_MASK
+FUTEX_BITSET_MATCH_ANY
 F_CLOSEM
 F_GETNOSIGPIPE
 F_GETOWN

src/unix/bsd/netbsdlike/netbsd/mod.rs

@@ -1302,6 +1302,29 @@ pub const F_SETNOSIGPIPE: ::c_int = 14;
 pub const F_MAXFD: ::c_int = 11;
 pub const F_GETPATH: ::c_int = 15;
 
+pub const FUTEX_WAIT: ::c_int = 0;
+pub const FUTEX_WAKE: ::c_int = 1;
+pub const FUTEX_FD: ::c_int = 2;
+pub const FUTEX_REQUEUE: ::c_int = 3;
+pub const FUTEX_CMP_REQUEUE: ::c_int = 4;
+pub const FUTEX_WAKE_OP: ::c_int = 5;
+pub const FUTEX_LOCK_PI: ::c_int = 6;
+pub const FUTEX_UNLOCK_PI: ::c_int = 7;
+pub const FUTEX_TRYLOCK_PI: ::c_int = 8;
+pub const FUTEX_WAIT_BITSET: ::c_int = 9;
+pub const FUTEX_WAKE_BITSET: ::c_int = 10;
+pub const FUTEX_WAIT_REQUEUE_PI: ::c_int = 11;
+pub const FUTEX_CMP_REQUEUE_PI: ::c_int = 12;
+pub const FUTEX_PRIVATE_FLAG: ::c_int = 1 << 7;
+pub const FUTEX_CLOCK_REALTIME: ::c_int = 1 << 8;
+pub const FUTEX_CMD_MASK: ::c_int = !(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME);
+pub const FUTEX_WAITERS: u32 = 1 << 31;
+pub const FUTEX_OWNER_DIED: u32 = 1 << 30;
+pub const FUTEX_SYNCOBJ_1: u32 = 1 << 29;
+pub const FUTEX_SYNCOBJ_0: u32 = 1 << 28;
+pub const FUTEX_TID_MASK: u32 = (1 << 28) - 1;
+pub const FUTEX_BITSET_MATCH_ANY: u32 = !0;
+
 pub const IP_RECVDSTADDR: ::c_int = 7;
 pub const IP_SENDSRCADDR: ::c_int = IP_RECVDSTADDR;
 pub const IP_RECVIF: ::c_int = 20;