Cygwin/X: Tidy up a bodge to avoid collision between X header and native Win32 API definitions of ATOM

Remove a bodge to avoid collision between X header and the native
Win32 API definitions of ATOM, use X11/Xwindows.h which exists to
address these issues

Consequently, include misc.h in winclipboardthread.c, to provide the
max() macro, as previously we were using the the one from windows.h

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>

hw/xwin/winclipboard.h

@@ -48,27 +48,12 @@
 /* X headers */
 #include <X11/X.h>
 #include <X11/Xatom.h>
-/* NOTE: For some unknown reason, including Xproto.h solves
- * tons of problems with including windows.h.  Unknowns reasons
- * are usually bad, so someone should investigate this.
- */
 #include <X11/Xproto.h>
 #include <X11/Xutil.h>
 #include <X11/Xlocale.h>
 
-/* Fixups to prevent collisions between Windows and X headers */
-#define ATOM			DWORD
-
-#ifndef __CYGWIN__
-#define sleep(x) Sleep (1000 * (x))
-#endif
-
 /* Windows headers */
-#ifndef XFree86Server
-#define XFree86Server
-#endif
-#include <windows.h>
-#undef XFree86Server
+#include <X11/Xwindows.h>
 
 
 /* Clipboard module constants */

hw/xwin/winclipboardthread.c

@@ -39,6 +39,7 @@
 #include <errno.h>
 #endif
 #include "X11/Xauth.h"
+#include "misc.h"
 
 
 /*