drop remains of cygwin support

Cygwin support doesn't seem to be used anymore, so it can be dropped.

Signed-off-by: Enrico Weigelt, metux IT consult <info@metux.net>

include/meson.build

@@ -406,8 +406,6 @@ xwin_data = configuration_data()
 xwin_data.set_quoted('DEFAULT_LOGDIR', log_dir)
 xwin_data.set('HAS_WINSOCK', host_machine.system() == 'windows' ? '1' : false,
               description: 'Use Windows sockets')
-xwin_data.set('HAS_DEVWINDOWS', host_machine.system() == 'cygwin' ? '1' : false,
-              description: 'Has /dev/windows for signaling new win32 messages')
 xwin_data.set('RELOCATE_PROJECTROOT', host_machine.system() == 'windows' ? '1' : false,
               description: 'Make paths relative to the xserver installation location')
 xwin_data.set10('ENABLE_DEBUG', enable_debugging)

include/os.h

@@ -345,7 +345,7 @@ xorg_backtrace(void);
 
 #include <signal.h>
 
-#if defined(WIN32) && !defined(__CYGWIN__)
+#if defined(WIN32)
 typedef _sigset_t sigset_t;
 #endif
 

include/xwin-config.h.meson.in

@@ -9,9 +9,6 @@
 /* Winsock networking */
 #mesondefine HAS_WINSOCK
 
-/* Cygwin has /dev/windows for signaling new win32 messages */
-#mesondefine HAS_DEVWINDOWS
-
 /* Switch on debug messages */
 #mesondefine ENABLE_DEBUG