bug#12471: Avoid some signal-handling races, and simplify.

[Paul Eggert]

On 09/22/2012 02:10 AM, Eli Zaretskii wrote:
> Which means 'sys_kill' will need to do everything that's expected from
> 'raise'. 

Unless I'm missing something, the only thing that Emacs will
expect from 'raise' is that it act like 'sys_kill' on itself,
so the proposed patch shouldn't affect what 'sys_kill' needs
to do.

> I was asking not to aggravate the situation, if it's possible.

Yes, but I don't see how the proposed patch aggravates the
situation.  It causes Emacs to execute the same Windows
primitives as before.  These primitives may have problems,
but those problems are the same problems as before.

I'm perhaps stating the obvious here, but just in case
I'm misunderstanding please bear with me: the Windows
substitutes for kill, raise, etc. need not support every
POSIX feature.  They need to support only the features that
Emacs uses.  So sys_raise need not support every feature that
POSIX requires for 'raise'; it needs to support only the
'raise' features that Emacs uses.  Likewise for 'sys_kill'
versus POSIX 'kill'.