[fpc-pascal] Ncurses unit and newer releases of ncurses

[Noel Duffy]

Running fpc 3.0.4 on Fedora 30.

The ncurses unit is based on version 5.6 of ncurses, according to 
constants defined in the source. The upstream ncurses is now at 6.2, and 
I wondered if there are plans afoot to upgrade the ncurses unit to 
support a more recent ncurses version. Newer releases support 256 
colours and additional attributes like italic on supported terminals.

I don't know if some part of the ncurses unit automatically generated 
from from the C sources, so I don't know how difficult this job actually 
is.

Cheers,
Noel