CMake build for xorp

Building

Basic build setup on Ubuntu 20.04.3 with setup:

CMake 3.16.3
GNU Make 4.2.1
GNU GCC 9.3.0
GNU G++ 9.3.0
GNU Bison 3.5.1
Glibc 2.31
Linux kernel 6.2.x

TODO List

readdir in libtecla (readdir_r deprecated since glibc 2.19)
Tests