[Test commit] Inherit main tid for the proxied main thread

Author: kleisauke

system/lib/pthread/library_pthread.c

@@ -906,7 +906,8 @@ static char** _main_argv;
 
 extern int __call_main(int argc, char** argv);
 
-static void* _main_thread(void* param) {
+static void* _main_thread(void* tid) {
+  pthread_self()->tid = (int)tid;
   // This is the main runtime thread for the application.
   emscripten_set_thread_name(pthread_self(), "Application main thread");
   return (void*)__call_main(_main_argc, _main_argv);
@@ -925,7 +926,7 @@ int emscripten_proxy_main(int argc, char** argv) {
   _main_argc = argc;
   _main_argv = argv;
   pthread_t thread;
-  int rc = pthread_create(&thread, &attr, _main_thread, NULL);
+  int rc = pthread_create(&thread, &attr, _main_thread, (void*)pthread_self()->tid);
   pthread_attr_destroy(&attr);
   return rc;
 }