I already committed fix for modular HEAD's hw/xfree86/os-support/xf86_OSlib.h

Fix sysmouse handling on DragonFly, mostly garbage arrived.
From Joerg Sonnenberger.

Here is patch for monolithic:
$NetBSD: patch-av,v 1.4 2006/02/01 20:21:59 joerg Exp $

--- programs/Xserver/hw/xfree86/os-support/xf86_OSlib.h.orig	2005-11-08
06:33:29.000000000 +0000
+++ programs/Xserver/hw/xfree86/os-support/xf86_OSlib.h
@@ -445,7 +445,7 @@ extern int errno;
 /* Kernel of *BSD                                                         */
 /**************************************************************************/
 #if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) || \
- defined(__NetBSD__) || defined(__OpenBSD__) || defined(__bsdi__)
+ defined(__NetBSD__) || defined(__OpenBSD__) || defined(__bsdi__) ||
defined(__DragonFly__)
 
 # include <sys/param.h>
 # if defined(__FreeBSD_version) && !defined(__FreeBSD_kernel_version)
@@ -470,11 +470,11 @@ extern int errno;
 #   endif
 #   ifdef SYSCONS_SUPPORT
 #    define COMPAT_SYSCONS
-#    if defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
+#    if defined(__NetBSD__) || defined(__OpenBSD__)
 #     include <machine/console.h>
 #    else
-#     if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
-#        if (__FreeBSD_kernel_version >= 410000)
+#     if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) ||
defined(__DragonFly__)
+#        if defined(__DragonFly__)  || (__FreeBSD_kernel_version >= 410000)
 #          include <sys/consio.h>
 #          include <sys/kbio.h>
 #        else
@@ -488,7 +488,7 @@ extern int errno;
 #   if defined(PCVT_SUPPORT)
 #    if !defined(SYSCONS_SUPPORT)
       /* no syscons, so include pcvt specific header file */
-#     if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) ||
defined(__DragonFly__)
+#     if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
 #      include <machine/pcvt_ioctl.h>
 #     else
 #      if defined(__NetBSD__) || defined(__OpenBSD__)
@@ -511,8 +511,8 @@ extern int errno;
 #    include <dev/wscons/wsconsio.h>
 #    include <dev/wscons/wsdisplay_usl_io.h>
 #   endif /* WSCONS_SUPPORT */
-#   if defined(__FreeBSD__) || defined(__FreeBSD_kernel__)
-#    if (__FreeBSD_kernel_version >= 500013)
+#   if defined(__FreeBSD__) || defined(__FreeBSD_kernel__) ||
defined(__DragonFly__)
+#    if defined(__FreeBSD_kernel_version) && (__FreeBSD_kernel_version >= 500013)
 #     include <sys/mouse.h>
 #    else
 #     undef MOUSE_GETINFO