Segfault using GC and PCL

pcl_and_gc.c

#include <gc/gc.h>
#include <pcl.h>
#include <stdio.h>

void coroutine(void *arg)
{
  int i;
  for (i = 0; i < 1000; ++i)
  {
    printf("%d\n", i);
    GC_malloc(1024);
  }
}

#define STACK_SIZE 32 * 1024

int main(int argc, char const *argv[])
{
  GC_init();
  void *stack = GC_malloc(STACK_SIZE);

  coroutine_t c = co_create(coroutine, 0, stack, STACK_SIZE);
  co_call(c);

  return 0;
}