Added X11 Xinerama support - fullscreen starts on screen 0

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40228

configure.in

@@ -602,6 +602,26 @@ CheckX11()
                     SYSTEM_LIBS="$SYSTEM_LIBS -lXv"
                 fi
             fi
+            AC_ARG_ENABLE(video-x11-xinerama,
+[  --enable-video-x11-xinerama   enable X11 Xinerama support [default=yes]],
+                            , enable_video_x11_xinerama=yes)
+            if test x$enable_video_x11_xinerama = xyes; then
+                AC_MSG_CHECKING(for X11 Xinerama support)
+                video_x11_xinerama=no
+                AC_TRY_COMPILE([
+                 #include <X11/Xlib.h>
+                 #include <X11/extensions/Xinerama.h>
+                ],[
+                 XineramaScreenInfo *xinerama;
+                ],[
+                video_x11_xinerama=yes
+                ])
+                AC_MSG_RESULT($video_x11_xinerama)
+                if test x$video_x11_xinerama = xyes; then
+                    CFLAGS="$CFLAGS -DHAVE_XINERAMA"
+                    SYSTEM_LIBS="$SYSTEM_LIBS -lXinerama"
+                fi
+            fi
         fi
     fi
 }