[FS#1411] OpenVPN build fails with --enable-pkcs11 in the Makefile

[LEDE Bugs]

A new Flyspray task has been opened.  Details are below. 

User who did this - Telefonorosso (Telefonorosso) 

Attached to Project - OpenWrt/LEDE Project
Summary - OpenVPN build fails with --enable-pkcs11 in the Makefile
Task Type - Build Failure
Category - Packages
Status - Unconfirmed
Assigned To - 
Operating System - All
Severity - Low
Priority - Very Low
Reported Version - lede-17.01
Due in Version - Undecided
Due Date - Undecided
Details - Problem Description
On Lede image builder under Debian i686 with 4.9.0 kernel, if I edit package/network/services/openvpn/Makefile and change:

--enable-pkcs11

build fails. The configure script cannot find pkcs11-helper dependency.

Proposed Resolution
Add the pkcs11-helper software in Lede

Steps to reproduce
nano [BUILD_DIR]/package/network/services/openvpn/Makefile
make package/openvpn/compile

Hardware is Dragino DT01 AR7xxx/AR9xxx based system.

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=1411