diff --git a/Zend/zend.h b/Zend/zend.h
index 5b1f9e90c28..6a9658aa3d7 100644
--- a/Zend/zend.h
+++ b/Zend/zend.h
@@ -45,7 +45,8 @@
 #include "zend_errors.h"
 #include "zend_alloc.h"
 
-#if SIZEOF_VOID_P == 8
+/* this is a workaround for a bug in gcc */
+#if SIZEOF_VOID_P == 8 || defined(__arch64__)
 typedef unsigned int zend_bool;
 #else
 typedef unsigned char zend_bool;