Merge branch 'PHP-5.6'

Conflicts:
	Zend/zend_vm_def.h
	Zend/zend_vm_execute.h

Zend/tests/generators/bug69419.phpt

@@ -0,0 +1,22 @@
+--TEST--
+Bug #69419: Returning compatible sub generator produces a warning
+--FILE--
+<?php
+
+function & genRefInner() {
+    $var = 1;
+    yield $var;
+}
+
+function & genRefOuter() {
+    return genRefInner();
+}
+
+foreach(genRefOuter() as $i) {
+    var_dump($i);
+}
+
+?>
+--EXPECTF--
+Notice: Only variable references should be returned by reference in %s on line %d
+int(1)