build-sys: Use ncursesw by default

build-sys: Use ncursesw by default

The existing build system would only require wide ncurses for
a wide watch and even if the library was there would not link
anything else to it.

The first issue which #123 made me think of, is if ncursesw
was there and ncurses is not, why not use ncursesw?

A more major issue is if programs such as slabtop are linked
to ncurses, then certain languages will display their text
wrong, as found in #237.

The days of assuming ASCII only is ok are over the build system
now does the following:
 1. If ncursesw is available use this for all relevant programs
 2. If ncursesw is not but ncurses is, use this instead
 3. If you enable 8bit watch and either disable ncurses or
    we cannot find ncursesw error at configure time.

In related news, I hate M4sh.

References:
 procps-ng/procps#123
 procps-ng/procps#237

Signed-off-by: Craig Small <csmall@dropbear.xyz>