emcc wikipedia.c -lpthread -o wikipedia.html -s TOTAL_MEMORY=268435456 -s PTHREAD_POOL_SIZE=40 -s USE_PTHREADS=1 --emrun 
emrun --browser firefox_nightly wikipedia.html

still waiting on run dependencies:
dependency: pthreads
(end of list)

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#define NUM_THREADS     5

void *perform_work(void *argument)
{
   int passed_in_value;

   passed_in_value = *((int *) argument);
   printf("Hello World! It's me, thread with argument %d!\n", passed_in_value);

   /* optionally: insert more useful stuff here */

   return NULL;
}

int main(void)
{
   pthread_t threads[NUM_THREADS];
   int thread_args[NUM_THREADS];
   int result_code, index;

   // create all threads one by one
   for (index = 0; index < NUM_THREADS; ++index) {
      thread_args[index] = index;
      printf("In main: creating thread %d\n", index);
      result_code = pthread_create(&threads[index], NULL, perform_work, (void *) &thread_args[index]);
      assert(0 == result_code);
   }

   // wait for each thread to complete
   for (index = 0; index < NUM_THREADS; ++index) {
      // block until thread 'index' completes
      result_code = pthread_join(threads[index], NULL);
      printf("In main: thread %d has completed\n", index);
      assert(0 == result_code);
   }

   printf("In main: All threads completed successfully\n");
   exit(EXIT_SUCCESS);
}

cmd = ['emrun', '--kill_start', '--kill_exit', '--timeout=15', '--silence_timeout=15', '--browser=firefox_nightly', out]

cd conformance/interfaces
run_all_tests.py

=== FINISHED ===
3 tests failed:
1-1.c, 2-1.c, 3-1.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>

static void *thread_func(void *vptr_args) {
    for (int i = 0; i < 20; i++) {
        puts("  b");
        sleep(1);
    }

    return NULL;
}

int main(void) {
    pthread_t thread;

    if (pthread_create(&thread, NULL, thread_func, NULL) != 0) {
        return EXIT_FAILURE;
    }

    for (int i = 0; i < 20; i++) {
        puts("a");
        sleep(1);
    }

    if (pthread_join(thread, NULL) != 0) {
        return EXIT_FAILURE;
    }

    return EXIT_SUCCESS;
}