diff -Naur libzip-1.1/src/ziptool.c libzip-1.1-p/src/ziptool.c
--- libzip-1.1/src/ziptool.c	2016-01-22 20:17:02.000000000 +0100
+++ libzip-1.1-p/src/ziptool.c	2016-01-30 12:35:28.066463560 +0100
@@ -52,6 +52,7 @@
 #include "zip.h"
 #include "compat.h"
 
+extern int optopt;
 zip_source_t *source_hole_create(const char *, int flags, zip_error_t *);
 
 typedef enum {