Merge branch '2.7' into 2.8

* 2.7:
  Using FQ name for PHP_VERSION_ID
  [Form] Fix \IntlDateFormatter timezone parameter usage to bypass PHP bug #66323
  Harden the debugging of Twig filters and functions
  bumped Symfony version to 2.7.29
  updated VERSION for 2.7.28
  update CONTRIBUTORS for 2.7.28
  updated CHANGELOG for 2.7.28

Author: fabpot

ClassCollectionLoader.php

@@ -232,7 +232,7 @@ public static function fixNamespaceDeclarations($source)
 
         $output .= self::compressCode($rawChunk);
 
-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
             // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
             unset($tokens, $rawChunk);
             gc_mem_caches();

ClassMapGenerator.php

@@ -12,7 +12,7 @@
 namespace Symfony\Component\ClassLoader;
 
 if (!defined('SYMFONY_TRAIT')) {
-    if (PHP_VERSION_ID >= 50400) {
+    if (\PHP_VERSION_ID >= 50400) {
         define('SYMFONY_TRAIT', T_TRAIT);
     } else {
         define('SYMFONY_TRAIT', 0);
@@ -72,7 +72,7 @@ public static function createMap($dir)
 
             $classes = self::findClasses($path);
 
-            if (PHP_VERSION_ID >= 70000) {
+            if (\PHP_VERSION_ID >= 70000) {
                 // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
                 gc_mem_caches();
             }

Tests/ClassMapGeneratorTest.php

@@ -108,7 +108,7 @@ public function getTestCreateMapTests()
             )),
         );
 
-        if (PHP_VERSION_ID >= 50400) {
+        if (\PHP_VERSION_ID >= 50400) {
             $data[] = array(__DIR__.'/Fixtures/php5.4', array(
                 'TFoo' => __DIR__.'/Fixtures/php5.4/traits.php',
                 'CFoo' => __DIR__.'/Fixtures/php5.4/traits.php',
@@ -119,7 +119,7 @@ public function getTestCreateMapTests()
             ));
         }
 
-        if (PHP_VERSION_ID >= 50500) {
+        if (\PHP_VERSION_ID >= 50500) {
             $data[] = array(__DIR__.'/Fixtures/php5.5', array(
                 'ClassCons\\Foo' => __DIR__.'/Fixtures/php5.5/class_cons.php',
             ));