[PATCH] Fix kill(0, $pid) on Windows

I broke the kill(0, $pid) behavior on Windows with change 29605
(the one implementing killpg()):

    http://public.activestate.com/cgi-bin/perlbrowse/p/29605

The problem is that OpenProcess() returns a HANDLE, but on error it
returns NULL and not the usual INVALID_HANDLE_VALUE. I assume the reason
for this is that at the kernel level, the INVALID_HANDLE_VALUE bit
pattern is the same as the pseudo handle for the current process.

The attached patch restores kill(0, $pid) behavior.

Cheers,
-Jan

• [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• Re: [PATCH] Fix kill(0, $pid) on Windows by Garrett Cooper
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• Re: [PATCH] Fix kill(0, $pid) on Windows by youshi10
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• killpg() on Windows by Jan Dubois
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Steve Hay
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois
• Re: [PATCH] Fix kill(0, $pid) on Windows by Garrett Cooper
• Re: [PATCH] Fix kill(0, $pid) on Windows by Garrett Cooper
• Re: [PATCH] Fix kill(0, $pid) on Windows by youshi10
• RE: [PATCH] Fix kill(0, $pid) on Windows by Jan Dubois