[jsf] How get the base URL via context path in JSF?

JSTL 1.2 variation leveraged from BalusC answer

<c:set var="baseURL" value="${pageContext.request.requestURL.substring(0, pageContext.request.requestURL.length() - pageContext.request.requestURI.length())}${pageContext.request.contextPath}/" />

<head>
  <base href="${baseURL}" />