add pos_copy(); pos->king[] set at higher level

src/position.c

@@ -62,6 +62,21 @@ pos_t *pos_dup(const pos_t *pos)
     return newpos;
 }
 
+/**
+ * pos_copy() - copy a position into another one.
+ * @from: &position to duplicate.
+ * @to: &destination position.
+ *
+ * Return a copy of @from into @to.
+ *
+ * @Return: @to.
+ */
+pos_t *pos_copy(const pos_t *from, pos_t *to)
+{
+    *to = *from;
+    return to;
+}
+
 /**
  * pos_del() - delete a position.
  * @pos: &position.
@@ -87,6 +102,7 @@ pos_t *pos_clear(pos_t *pos)
     pos->turn = WHITE;
 
     /* move_do/undo position state */
+    pos->key = 0;
     pos->en_passant = SQUARE_NONE;
     pos->castle = 0;
     pos->clock_50 = 0;
@@ -336,9 +352,9 @@ bool pos_ok(const pos_t *pos, const bool strict)
 
     /* force BUG_ON and WARN_ON */
 #   pragma push_macro("BUG_ON")
-#   pragma push_macro("WARN_ON")
 #   undef BUG_ON
 #   define BUG_ON
+#   pragma push_macro("WARN_ON")
 #   undef WARN_ON
 #   define WARN_ON