Add m_next2u, analogous to m_next2m and next2u

src/wizard.c

@@ -94,7 +94,7 @@ amulet(void)
             continue;
         if (mtmp->iswiz && mtmp->msleeping && !rn2(40)) {
             mtmp->msleeping = 0;
-            if (!next2u(mtmp->mx, mtmp->my))
+            if (!m_next2u(mtmp))
                 You(
       "get the creepy feeling that somebody noticed your taking the Amulet.");
             return;