std: replace `LazyBox` with `OnceBox`

This PR replaces the `LazyBox` wrapper used to allocate the pthread primitives with `OnceBox`, which has a more familiar API mirroring that of `OnceLock`. This cleans up the code in preparation for larger changes like #128184 (from which this PR was split) and allows some neat optimizations, like avoid an acquire-load of the allocation pointer in `Mutex::unlock`, where the initialization of the allocation must have already been observed.

Additionally, I've gotten rid of the TEEOS `Condvar` code, it's just a duplicate of the pthread one anyway and I didn't want to repeat myself.

1 files changed, 4 insertions, 4 deletions

diff --git a/library/std/src/sys/sync/rwlock/teeos.rs b/library/std/src/sys/sync/rwlock/teeos.rs
index ef9b1ab5154..76343022383 100644
--- a/library/std/src/sys/sync/rwlock/teeos.rs
+++ b/library/std/src/sys/sync/rwlock/teeos.rs
@@ -14,22 +14,22 @@ impl RwLock {
 
     #[inline]
     pub fn read(&self) {
-        unsafe { self.inner.lock() };
+        self.inner.lock()
     }
 
     #[inline]
     pub fn try_read(&self) -> bool {
-        unsafe { self.inner.try_lock() }
+        self.inner.try_lock()
     }
 
     #[inline]
     pub fn write(&self) {
-        unsafe { self.inner.lock() };
+        self.inner.lock()
     }
 
     #[inline]
     pub unsafe fn try_write(&self) -> bool {
-        unsafe { self.inner.try_lock() }
+        self.inner.try_lock()
     }
 
     #[inline]