Install libopenconnect-dev by entering the following commands in the terminal:
sudo apt update sudo apt install libopenconnect-dev
Description:
open client for Cisco AnyConnect VPN - development files
OpenConnect is a client for Cisco's AnyConnect SSL VPN, which is supported by the ASA5500 Series, by IOS 12.4(9)T or later on Cisco SR500, 870, 880, 1800, 2800, 3800, 7200 Series and Cisco 7301 Routers, and probably others. OpenConnect also supports the Pulse Connect Secure SSL VPN, formerly known as the Juniper SSL VPN or the Junos Pulse VPN. . This package provides the header and development files.
Homepage: http://www.infradead.org/openconnect/
Version: 7.08-3
Section: universe/libdevel