variation of https://github.com/less/less.js/issues/965#issuecomment-17483536 designed to duplicate the content of a media query for IE8

less-mq-ie.less

/*
  Usage: the caller must have .content declared in its scope!
*/
.mobile() {
  @media all and (min-width: 480px) {
    .content;
  }
  .ie-lt-ie9 &{
    .content;
  }
}

// demo: try at http://less2css.org/
.foo {
  .content() { //this will be injected into .mobile mixin
    width: 500px;
    font-size: 100%;
  } .mobile;
}