--- gnupg-1.4.23.orig/include/iobuf.h	2016-04-22 09:30:18.000000000 +0200
+++ gnupg-1.4.23/include/iobuf.h	2021-09-17 16:07:15.504427621 +0200
@@ -72,6 +72,8 @@ struct iobuf_struct {
 #ifndef EXTERN_UNLESS_MAIN_MODULE
 #if defined (__riscos__) && !defined (INCLUDED_BY_MAIN_MODULE)
 #define EXTERN_UNLESS_MAIN_MODULE extern
+#elif defined (__GNUC__) && __GNUC__ >= 10
+#define EXTERN_UNLESS_MAIN_MODULE __attribute__((__common__))
 #else
 #define EXTERN_UNLESS_MAIN_MODULE 
 #endif