(OVERLAY_POSITION): Use XGCTYPE.

diff --git a/src/buffer.h b/src/buffer.h
index e5638bb..de20ae7 100644 (file)
--- a/src/buffer.h
+++ b/src/buffer.h
@@ -386,7 +386,7 @@ extern Lisp_Object Vtransient_mark_mode;
    We assume you know which buffer it's pointing into.  */
 
 #define OVERLAY_POSITION(P)                                    \
- (MARKERP ((P)) ? marker_position ((P)) : (abort (), 0))
+ (XGCTYPE ((P)) == Lisp_Marker ? marker_position ((P)) : (abort (), 0))
 
 /* Allocation of buffer text.  */