question about threads_keepalive variable.

[wind0ws]

Hi, thanks for this awesome lib.

In thpool.c (line 37), here is static volatile int threads_keepalive; , why not put threads_keepalive on struct thpool_?

Assume the following scenario:

1. Create thread pool A (Now threads_keepalive is set to 1);
2. Call add_task on thread pool A;
3. Create thread pool B (Now threads_keepalive is set to 1);
4. Call add_task on thread pool B;
5. Destroy thread pool A (Now threads_keepalive is set to 0);
6. Call add_task on thread pool B ; ( task won't execute, because of threads_keepalive == 0 )

[forGGe]

Just stumbled with similar issue. In my application, thread pool B isn't scheduling tasks if thread pool A is destroyed.