linux-user/syscall.c: handle FUTEX_WAIT_BITSET in do_futex

Upstream libc has recently changed to start using
FUTEX_WAIT_BITSET instead of FUTEX_WAIT and this
is causing do_futex to return -TARGET_ENOSYS.

Pass bitset in val3 to sys_futex which will be
ignored by kernel for the FUTEX_WAIT case.
Signed-off-by: NJohn Rigby <john.rigby@linaro.org>
Signed-off-by: NRiku Voipio <riku.voipio@linaro.org>

linux-user/syscall.c

@@ -4922,6 +4922,7 @@ static int do_futex(target_ulong uaddr, int op, int val, target_ulong timeout,
 #endif
     switch (base_op) {
     case FUTEX_WAIT:
+    case FUTEX_WAIT_BITSET:
         if (timeout) {
             pts = &ts;
             target_to_host_timespec(pts, timeout);
@@ -4929,7 +4930,7 @@ static int do_futex(target_ulong uaddr, int op, int val, target_ulong timeout,
             pts = NULL;
         }
         return get_errno(sys_futex(g2h(uaddr), op, tswap32(val),
-                         pts, NULL, 0));
+                         pts, NULL, val3));
     case FUTEX_WAKE:
         return get_errno(sys_futex(g2h(uaddr), op, val, NULL, NULL, 0));
     case FUTEX_FD: