darwin: use default stack size for fsevents pthread on macOS 10.15+

This fixes `SIGBUS` crashes on macOS 10.15 due to FSEvents code
attempting to allocate large arrays on the stack.

The existing size (`4 * PTHREAD_STACK_MIN` or 32KB) causes a stack
overflow when more than ~1000 events are received at once. Removing the
manual `pthread_attr_setstacksize` call here defaults to a stack size of
512KB.

Fixes: nodejs/node#37697
Refs: joyent/libuv#964

src/unix/fsevents.c

@@ -595,8 +595,6 @@ static int uv__fsevents_global_init(void) {
 static int uv__fsevents_loop_init(uv_loop_t* loop) {
   CFRunLoopSourceContext ctx;
   uv__cf_loop_state_t* state;
-  pthread_attr_t attr_storage;
-  pthread_attr_t* attr;
   int err;
 
   if (loop->cf_state != NULL)
@@ -641,25 +639,10 @@ static int uv__fsevents_loop_init(uv_loop_t* loop) {
     goto fail_signal_source_create;
   }
 
-  /* In the unlikely event that pthread_attr_init() fails, create the thread
-   * with the default stack size. We'll use a little more address space but
-   * that in itself is not a fatal error.
-   */
-  attr = &attr_storage;
-  if (pthread_attr_init(attr))
-    attr = NULL;
-
-  if (attr != NULL)
-    if (pthread_attr_setstacksize(attr, 4 * PTHREAD_STACK_MIN))
-      abort();
-
   loop->cf_state = state;
 
   /* uv_thread_t is an alias for pthread_t. */
-  err = UV__ERR(pthread_create(&loop->cf_thread, attr, uv__cf_loop_runner, loop));
-
-  if (attr != NULL)
-    pthread_attr_destroy(attr);
+  err = UV__ERR(pthread_create(&loop->cf_thread, NULL, uv__cf_loop_runner, loop));
 
   if (err)
     goto fail_thread_create;