randr: Add RRConstrainCursorHarder

Confine cursor motion to within the bounds of a single CRTC, iff all the
CRTCs within a ScreenRec are reachable from each other.  If not you get
the same "cursor floats within the bounding rect" behaviour you get now.

v3:
- Incorporate review feedback from Christopher James Halse Rogers
v4:
- Add mode field.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

randr/randrstr.h

@@ -297,6 +297,7 @@ typedef struct _rrScrPriv {
     int			    rate;
     int			    size;
 #endif
+    Bool                   discontiguous;
 } rrScrPrivRec, *rrScrPrivPtr;
 
 extern _X_EXPORT DevPrivateKeyRec rrPrivKeyRec;
@@ -700,6 +701,9 @@ ProcRRGetPanning (ClientPtr client);
 int
 ProcRRSetPanning (ClientPtr client);
 
+void
+RRConstrainCursorHarder (DeviceIntPtr, ScreenPtr, int, int *, int *);
+
 /* rrdispatch.c */
 extern _X_EXPORT Bool
 RRClientKnowsRates (ClientPtr	pClient);