Rename getline with get_line to avoid collision with getline(3).

[Thomas Nikolajsen]

Thanks for fixing style issues also, but
2 spaces after full stop in code comments *is* dfy style, according to style(9) man page.

 -thomas

https://leaf.dragonflybsd.org/cgi/web-man?command=style&section=9

>http://lists.dragonflybsd.org/pipermail/commits/2016-August/624416.html
>commit cae2835b6b4ebad97f7a0b45157102f433a3c656
>Author: zrj <rimvydas.jasinskas at gmail.com>
>Date:   Sat Aug 20 20:16:42 2016 +0300
>
>    Rename getline with get_line to avoid collision with getline(3).
>    
>    Just as it was recently done over at FreeBSD.
>    While there, perform some style changes too (could not resist that).
>    Only readline() -> read_line() functional change was intended.