I am trying to setup Openconnect Server on my Ubuntu VPS and first I have to compile it, but everytime i run ./configure I get 2 errors:

configure: WARNING: ***

*** libprotobuf-c was not found.

***

checking for libev... no

configure: error: ***

*** libev4 was not found.

***

When I try to install libprotobuf-c I get the following output

root@MY_VPS_NAME:~# apt install libprotobuf-c

Reading package lists... Done

Building dependency tree       

Reading state information... Done

E: Unable to locate package libprotobuf-c

and when I try to install libev4 I get the following output:

root@MY_VPS_NAME:~# apt install libev4

Reading package lists... Done

Building dependency tree       

Reading state information... Done

libev4 is already the newest version.

The following packages were automatically installed and are no longer required:

  linux-headers-3.19.0-15 linux-headers-3.19.0-15-generic linux-image-3.19.0-15-generic linux-image-extra-3.19.0-15-generic

Use 'apt-get autoremove' to remove them.

0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

root@MY_VPS_NAME:~# 

VPS is Running: ubuntu-15.04-x86_64
Thanks,
~WC