Index: /trunk/processor/head.m4
===================================================================
--- /trunk/processor/head.m4	(revision 93)
+++ /trunk/processor/head.m4	(revision 94)
@@ -201,5 +201,5 @@
 #endif
 		SET_IF_SAME_NAME(__call);
-#if PHP_MAJOR_VERSION >= 6
+#if defined(ZEND_ENGINE_2_2) || PHP_MAJOR_VERSION >= 6
 		SET_IF_SAME_NAME(__tostring);
 #endif
Index: /trunk/processor/processor.m4
===================================================================
--- /trunk/processor/processor.m4	(revision 93)
+++ /trunk/processor/processor.m4	(revision 94)
@@ -348,5 +348,5 @@
 	COPY(__unset)
 	COPY(__isset)
-# if PHP_MAJOR_VERSION >= 6
+# if defined(ZEND_ENGINE_2_2) || PHP_MAJOR_VERSION >= 6
 	COPY(__tostring)
 # endif