bug#34618: 26.1.92; timerfd interface causes slowdown on Cygwin

[Ken Brown]

On 3/9/2019 2:42 PM, Eli Zaretskii wrote:
>> From: Ken Brown <kbrown@cornell.edu>
>> CC: "34618@debbugs.gnu.org" <34618@debbugs.gnu.org>
>> Date: Sat, 9 Mar 2019 19:27:34 +0000
>>
>> The Cygwin problems with the timerfd functions have been fixed as of
>> cygwin-3.0.2, so I've re-enabled the use of these functions on the master
>> branch.  To play it safe, we should probably leave them disabled on the 
>> emacs-26
>> branch.
> 
> Isn't there a way to get at the version of Cygwin at run time?  I
> think the best solution is to allow timerfd functions only for
> versions whose support is not buggy, and that's not a compile-time
> decision, right?

Good idea.  How's the attached?

Ken

0001-Use-a-runtime-test-for-timerfd-on-Cygwin-Bug-34618.patch
Description: 0001-Use-a-runtime-test-for-timerfd-on-Cygwin-Bug-34618.patch