fix int/UInt messup.

C/dlmalloc.c

@@ -185,7 +185,7 @@ Yap_add_memory_hole(ADDR start, ADDR end)
   }
   Yap_MemoryHoles[Yap_NOfMemoryHoles].start = start;
   Yap_MemoryHoles[Yap_NOfMemoryHoles].end = end;
-  Yap_HoleSize += start-end;
+  Yap_HoleSize += (UInt)(start-end);
   Yap_NOfMemoryHoles++;
 }