Save states work poorly during loading screens in meatboy about libtas

[Matte27]

The following seems to cause it fairly consistently

1. Reach a certain point (like getting the last key in chad)
2. Load a savestate before said point
3. Load a different savestate before said point
4. Tool freezes and closing it is required to get it working again

[clementgallet]

This might have been fixed by 748d54e

[Matte27]

Not yet fixed

[clementgallet]

Freezes happen because the game closes a thread and creates another thread immediately. Pthread library recycles the thread, so the new thread has the same pthread id, but is a different process. When trying to suspend this thread for a future state saving/loading, the signal fails to reach the thread, so the thread is still active, and the tool infinitely waits for this thread to unsuspend.

[clementgallet]

This should be fixed by 384d881. Now both pthread id and process tid must be identical for a matched thread.