https://github.com/letoram/xarcan/commit/c6173b4f6682

../hw/kdrive/arcan/arcan.c:1523:21: error: incompatible function pointer types initializing 'present_abort_vblank_ptr' (aka 'void (*)(struct _rrCrtc *, unsigned long, unsigned long)') with an expression of type 'void (void *)' [-Wincompatible-function-pointer-types]
    .abort_vblank = arcanPresentAbortVblank,
                    ^~~~~~~~~~~~~~~~~~~~~~~
../hw/kdrive/arcan/arcan.c:1704:25: warning: incompatible pointer types passing 'miPointerSpriteFuncRec *' (aka 'struct _miPointerSpriteFuncRec *') to parameter of type 'miPointerScreenFuncPtr' (aka 'struct _miPointerScreenFuncRec *') [-Wincompatible-pointer-types]
                        &ArcanPointerSpriteFuncs, FALSE);
                        ^~~~~~~~~~~~~~~~~~~~~~~~

--- hw/kdrive/arcan/arcan.c.orig	2020-11-29 15:29:55 UTC
+++ hw/kdrive/arcan/arcan.c
@@ -1458,11 +1458,9 @@ static int arcanPresentGetUstMsc(RRCrtcPtr crtc, CARD6
     return 0;
 }
 
-static void arcanPresentAbortVblank(void *data)
+static void arcanPresentAbortVblank(RRCrtcPtr crtc, uint64_t evid, uint64_t msc)
 {
-    struct ms_present_vblank_event *event = data;
     trace("present:vblank abort");
-    free(event);
 }
 
 static int arcanPresentQueueVblank(RRCrtcPtr crtc, uint64_t evid, uint64_t msc)
@@ -1701,7 +1699,7 @@ arcanCursorInit(ScreenPtr screen)
 
     miPointerInitialize(screen,
                         &ArcanPointerSpriteFuncs,
-                        &ArcanPointerSpriteFuncs, FALSE);
+                        &ArcanPointerScreenFuncs, FALSE);
 
     return TRUE;
 }