Auto merge of #96393 - joboet:pthread_parker, r=thomcc

std: directly use pthread in UNIX parker implementation

`Mutex` and `Condvar` are being replaced by more efficient implementations, which need thread parking themselves (see #93740). Therefore we should use the `pthread` synchronization primitives directly. Also, we can avoid allocating the mutex and condition variable because the `Parker` struct is being placed in an `Arc` anyways.

This basically is just a copy of the current `Mutex` and `Condvar` code, which will however be removed (again, see #93740). An alternative implementation could be to use dedicated private `OsMutex` and `OsCondvar` types, but all the other platforms supported by std actually have their own thread parking primitives.

I used `Pin` to guarantee a stable address for the `Parker` struct, while the current implementation does not, rather using extra unsafe declaration. Since the thread struct is shared anyways, I assumed this would not add too much clutter while being clearer.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/test/debuginfo/thread.rs b/src/test/debuginfo/thread.rs
index 531c37a3421..388d50c5cdc 100644
--- a/src/test/debuginfo/thread.rs
+++ b/src/test/debuginfo/thread.rs
@@ -14,7 +14,7 @@
 //
 // cdb-command:dx t,d
 // cdb-check:t,d              : [...] [Type: std::thread::Thread *]
-// cdb-check:    [...] inner            : {...} [Type: alloc::sync::Arc<std::thread::Inner>]
+// cdb-check:[...] inner [...][Type: core::pin::Pin<alloc::sync::Arc<std::thread::Inner> >]
 
 use std::thread;