diff --git a/core/lib/Drupal/Component/Utility/HttpQuery.php b/core/lib/Drupal/Component/Utility/HttpQuery.php
index c4050c0..cbdb33b 100644
--- a/core/lib/Drupal/Component/Utility/HttpQuery.php
+++ b/core/lib/Drupal/Component/Utility/HttpQuery.php
@@ -12,8 +12,18 @@ class HttpQuery {
   /**
    * Parses an array into a valid, rawurlencoded query string.
    *
-   * This differs from http_build_query() as we need to rawurlencode() (instead of
-   * urlencode()) all query parameters.
+   * This function does the same as http_build_query() but it is using
+   * rawurlencode instead of urlencode.
+   *
+   * rawurlencode() is RFC3986 compliant, and as a consequence RFC3987
+   * compliant. The latter defines the required format of "URLs" in HTML5.
+   * urlencode() is almost the same as rawurlencode(), except that it encodes
+   * spaces as "+" instead of "%20". This makes its result non compliant to
+   * RFC3986 and as a consequence non compliant to RFC3987 and as a consequence
+   * not valid as a "URL" in HTML5.
+   *
+   * @todo Remove this function once PHP 5.4 is required as we can use just
+   *   http_build_query() directly.
    *
    * @param array $query
    *   The query parameter array to be processed, e.g. $_GET.
@@ -28,6 +38,11 @@ class HttpQuery {
    * @ingroup php_wrappers
    */
   public static function buildQuery(array $query, $parent = '') {
+    // Use the php method for it, on PHP 5.4 and newer.
+    if (version_compare(PHP_VERSION, '5.4.0') < 0) {
+      return http_build_query($query, NULL, NULL, PHP_QUERY_RFC3986);
+    }
+
     $params = array();
 
     foreach ($query as $key => $value) {