bug#19909: [PATCH] Error out if with-file-notification=w32 is specified on cygwin

[Robert Pluim]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Robert Pluim <rpluim@gmail.com>
>> Date: Fri, 20 Feb 2015 10:47:36 +0100
>> 
>> It's a combination that won't compile, so it's probably best to error
>> out during configure.
>
> Why doesn't it compile?  Perhaps it's better to allow it to compile,
> than to error out.

I guess whoever put the following in w32.h had his reasons:

#ifdef CYGWIN
#error "w32.h is not compatible with Cygwin"
#endif


In file included from w32notify.c:95:0:
w32.h:23:2: error: #error "w32.h is not compatible with Cygwin"
 #error "w32.h is not compatible with Cygwin"
  ^
In file included from ../lib/sys/types.h:28:0,
                 from ../lib/signal.h:49,
                 from /usr/include/machine/setjmp.h:357,
                 from /usr/include/setjmp.h:10,
                 from lisp.h:24,
                 from w32notify.c:92: