message: update Array::append copy the array value.
diff: @@ -37,6 +37,10 @@ extern "C"
  #include <ext/standard/info.h>
  #include <ext/standard/php_array.h>
  #include "ext/standard/php_var.h"
  +
  +#if PHP_MAJOR_VERSION < 7
  +#error "only supports PHP7 or later."
  +#endif
  }
  #include <unordered_map>
  @@ -399,8 +403,10 @@ public:
  }
  void append(Array &v)
  {
  - zval_add_ref(v.ptr());
  - add_next_index_zval(ptr(), v.ptr());
  + zend_array *arr = zend_array_dup(Z_ARR_P(v.ptr()));
  + zval array;
  + ZVAL_ARR(&array, arr);
  + add_next_index_zval(ptr(), &array);
  }
  //------------------------------------
  void set(const char *key, Variant &v)
  