Implement sync2.Recursive_Mutex using WaitOnAddress and friends on Windows

core/sync/sync2/primitives_pthreads.odin

@@ -5,6 +5,7 @@ package sync2
 when #config(ODIN_SYNC_USE_PTHREADS, true) {
 
 import "core:time"
+import "core:runtime"
 import "core:sys/unix"
 
 _Mutex_State :: enum i32 {
@@ -120,6 +121,53 @@ _rw_mutex_try_shared_lock :: proc(rw: ^RW_Mutex) -> bool {
 	return false;
 }
 
+
+_Recursive_Mutex :: struct {
+	owner:     int,
+	recursion: int,
+	mutex: Mutex,
+}
+
+_recursive_mutex_lock :: proc(m: ^Recursive_Mutex) {
+	tid := runtime.current_thread_id();
+	if tid != m.impl.owner {
+		mutex_lock(&m.impl.mutex);
+	}
+	// inside the lock
+	m.impl.owner = tid;
+	m.impl.recursion += 1;
+}
+
+_recursive_mutex_unlock :: proc(m: ^Recursive_Mutex) {
+	tid := runtime.current_thread_id();
+	assert(tid == m.impl.owner);
+	m.impl.recursion -= 1;
+	recursion := m.impl.recursion;
+	if recursion == 0 {
+		m.impl.owner = 0;
+	}
+	if recursion == 0 {
+		mutex_unlock(&m.impl.mutex);
+	}
+	// outside the lock
+
+}
+
+_recursive_mutex_try_lock :: proc(m: ^Recursive_Mutex) -> bool {
+	tid := runtime.current_thread_id();
+	if m.impl.owner == tid {
+		return mutex_try_lock(&m.impl.mutex);
+	}
+	if !mutex_try_lock(&m.impl.mutex) {
+		return false;
+	}
+	// inside the lock
+	m.impl.owner = tid;
+	m.impl.recursion += 1;
+	return true;
+}
+
+
 _Cond :: struct {
 	pthread_cond: unix.pthread_cond_t,
 }