diff --git a/vpnor/test/write_patch_resize.cpp b/vpnor/test/write_patch_resize.cpp
index 5d39802..ff2558b 100644
--- a/vpnor/test/write_patch_resize.cpp
+++ b/vpnor/test/write_patch_resize.cpp
@@ -13,7 +13,10 @@
 #include "config.h"
 #include "common.h"
 #include "mbox.h"
+
+extern "C" {
 #include "flash.h"
+}
 
 #include "vpnor/test/tmpd.hpp"