Fix clang errors when pendantic errors enabled

I've been compiling with:

```
  set -lx cflags '-std=c99 -Werror=pedantic -pedantic-errors'
```

But compilation would fail with the following:

```
cont.c:296:90: error: format specifies type 'void *' but the argument has type 'struct fiber_pool_stack *' [-Werror,-Wformat-pedantic]
    if (DEBUG) fprintf(stderr, "fiber_pool_stack_alloca(%p): %"PRIuSIZE"/%"PRIuSIZE"\n", stack, offset, stack->available);
                                                        ~~                               ^~~~~
cont.c:467:24: error: format specifies type 'void *' but the argument has type 'struct fiber_pool *' [-Werror,-Wformat-pedantic]
                count, fiber_pool, fiber_pool->used, fiber_pool->count, size, fiber_pool->vm_stack_size);
                       ^~~~~~~~~~
cont.c:588:83: error: format specifies type 'void *' but the argument has type 'struct fiber_pool_vacancy *' [-Werror,-Wformat-pedantic]
    if (DEBUG) fprintf(stderr, "fiber_pool_stack_acquire: %p used=%"PRIuSIZE"\n", fiber_pool->vacancies, fiber_pool->used);
                                                          ~~                      ^~~~~~~~~~~~~~~~~~~~~
cont.c:736:76: error: format specifies type 'void *' but the argument has type 'rb_fiber_t *' (aka 'struct rb_fiber_struct *')
      [-Werror,-Wformat-pedantic]
    if (DEBUG) fprintf(stderr, "fiber_stack_release: %p, stack.base=%p\n", fiber, fiber->stack.base);
```

This commit just fixes the pedantic errors

0 files changed, 0 insertions, 0 deletions