btif_sock: Use atomic operations for thread_handle

#define LOG_TAG "bt_btif_sock"

#include <atomic>

#include <base/logging.h>

#include <hardware/bluetooth.h>

static void btsock_signaled(int fd, int type, int flags, uint32_t user_id);

static int thread_handle = -1;

static std::atomic_int thread_handle{-1};

static thread_t* thread;

btsock_interface_t* btif_sock_get_interface(void) {

}

void btif_sock_cleanup(void) {

  if (thread_handle == -1) return;

  int saved_handle = thread_handle;

  if (std::atomic_exchange(&thread_handle, -1) == -1) return;

  thread_stop(thread);

  thread_join(thread);

  btsock_thread_exit(thread_handle);

  btsock_thread_exit(saved_handle);

  btsock_rfc_cleanup();

  btsock_sco_cleanup();

  btsock_l2cap_cleanup();

  thread_free(thread);

  thread_handle = -1;

  thread = NULL;

}