these all use futex() (inaccurate comments)

std/event/lock.zig

@@ -7,7 +7,7 @@ const AtomicOrder = builtin.AtomicOrder;
 const Loop = std.event.Loop;
 
 /// Thread-safe async/await lock.
-/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// coroutines which are waiting for the lock are suspended, and
 /// are resumed when the lock is released, in order.
 /// Allows only one actor to hold the lock.
 pub const Lock = struct {

std/event/locked.zig

@@ -3,7 +3,7 @@ const Lock = std.event.Lock;
 const Loop = std.event.Loop;
 
 /// Thread-safe async/await lock that protects one piece of data.
-/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// coroutines which are waiting for the lock are suspended, and
 /// are resumed when the lock is released, in order.
 pub fn Locked(comptime T: type) type {
     return struct {

std/event/rwlock.zig

@@ -7,7 +7,7 @@ const AtomicOrder = builtin.AtomicOrder;
 const Loop = std.event.Loop;
 
 /// Thread-safe async/await lock.
-/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// coroutines which are waiting for the lock are suspended, and
 /// are resumed when the lock is released, in order.
 /// Many readers can hold the lock at the same time; however locking for writing is exclusive.
 /// When a read lock is held, it will not be released until the reader queue is empty.

std/event/rwlocked.zig

@@ -3,7 +3,7 @@ const RwLock = std.event.RwLock;
 const Loop = std.event.Loop;
 
 /// Thread-safe async/await RW lock that protects one piece of data.
-/// Does not make any syscalls - coroutines which are waiting for the lock are suspended, and
+/// coroutines which are waiting for the lock are suspended, and
 /// are resumed when the lock is released, in order.
 pub fn RwLocked(comptime T: type) type {
     return struct {