Signals and an exiting thread

[David Xu]

Kostik Belousov wrote:

> I agree that postponing assignment of the thread for signal delivery
> till the actual delivery occurs is the proper fix. I tried to cheat
> in my previous patch. Below is an experimental change that did very
> minimal testing.
> <snip>

Even if the signal is put into process's signal queue, it is still
possible that signal notification is lost because selected thread
exits before seeing it, if other threads are sleeping, they are
not notified, this leaves signal in process queue long time before
it can be delivered to userland.