$OpenBSD: patch-include_tool_tool_interactive_h,v 1.1 2019/11/08 14:43:53 sthen Exp $

Index: include/tool/tool_interactive.h
--- include/tool/tool_interactive.h.orig
+++ include/tool/tool_interactive.h
@@ -27,6 +27,7 @@
 #define __TOOL_INTERACTIVE_H
 
 #include <string>
+#include <functional>
 
 #include <tool/tool_event.h>
 #include <tool/tool_base.h>
