xi: More warning cleanup for input

Lots more const char stuff.

Remove duplicate defs of CoreKeyboardProc and CorePointerProc from
test/xi2/protocol-common.c

Signed-off-by: Keith Packard <keithp@keithp.com>
Reviewed-by: Adam Jackson <ajax@redhat.com>

Xi/extinit.c

@@ -1169,8 +1169,8 @@ IResetProc(ExtensionEntry * unused)
     EventSwapVector[DevicePropertyNotify] = NotImplemented;
     RestoreExtensionEvents();
 
-    free(xi_all_devices.name);
-    free(xi_all_master_devices.name);
+    free((void *) xi_all_devices.name);
+    free((void *) xi_all_master_devices.name);
 
     XIBarrierReset();
 }