--- a/src/libmtp.c	2017-06-10 22:35:54.000000000 +0800
+++ b/src/libmtp.c	2021-08-04 19:17:57.464456535 +0800
@@ -44,6 +44,7 @@
 #include "util.h"
 
 #include "mtpz.h"
+int use_mtpz;
 
 #include <stdarg.h>
 #include <stdlib.h>
--- a/src/mtpz.h	2014-08-25 02:41:04.000000000 +0800
+++ b/src/mtpz.h	2021-08-04 19:17:03.819790448 +0800
@@ -45,7 +45,7 @@
 
 #endif
 
-int use_mtpz;
+extern int use_mtpz;
 
 #endif /* LIBMTP_H_INCLUSION_GUARD */