diff --git a/include/QF/qtypes.h b/include/QF/qtypes.h
index b37874305..5647f685b 100644
--- a/include/QF/qtypes.h
+++ b/include/QF/qtypes.h
@@ -53,6 +53,7 @@ typedef uint8_t byte;
 #endif
 
 #if __STDC_VERSION__ < 202000
+#define auto __auto_type
 #ifndef _DEF_BOOL_
 # define _DEF_BOOL_
 // KJB Undefined true and false defined in SciTech's DEBUG.H header