Improvement pack : Makefile rewrite + Menu + Visual line count + Crash fixes

[zedee]

Hello! I'd like to add some improvements, as well as the first steps for advancing in some of the ToDo topics, such as creating a menu system.

I'm thinking of giving this cute app a functional use besides its educative purpose, such as a visual regex tester for those who are not as experienced (e.g. myself) on this art.

Relevant changes:

• Make it easier to just run "make and forget" so it compiles out of the box on different systems and environments. It works where I've tested so far. No guarantees about other flavors, though I'd like to have some feedback.
• Added a menu (some functions are visible but not yet implemented, all selections except 'exit' will bring to the main loop).
• Added visual line count.
• Fixed some issues and app crashing in other systems such as ArchLinux.

I've tested and compiled it successfully on few random different systems and OS flavors such as:

• OpenIndiana 2023-10 (call it a SunOS if you want).
• ArchLinux 2023 (VM).
• Debian 10 Buster on a sunxi armv71 (this is an orangePI PC).
• Debian 12 Bookworm on my dev pc (generic x64).

I'm not sure if I'm doing this PR correctly or go slower... but anyway repo is 10 years forgotten, so I thought it wouldn't matter.

By the way, I do not have too much experience on C++ but C, so it's possible I'm doing things too much the 'C' way...

Cheers!