diff --git a/Zend/zend_map_ptr.h b/Zend/zend_map_ptr.h
index aa726e0cdd3..0ab1a357eec 100644
--- a/Zend/zend_map_ptr.h
+++ b/Zend/zend_map_ptr.h
@@ -19,7 +19,7 @@
 #ifndef ZEND_MAP_PTR_H
 #define ZEND_MAP_PTR_H
 
-#include "zend_portability.h"
+#include "zend_portability.h" // for BEGIN_EXTERN_C
 
 #define ZEND_MAP_PTR_KIND_PTR           0
 #define ZEND_MAP_PTR_KIND_PTR_OR_OFFSET 1
@@ -69,6 +69,8 @@
 # error "Unknown ZEND_MAP_PTR_KIND"
 #endif
 
+typedef struct _zend_string zend_string;
+
 BEGIN_EXTERN_C()
 
 ZEND_API void  zend_map_ptr_reset(void);