If ncurses was built with the --with-termlib switch enabled, tgoto, tgetent
and tgetstr move to libtinfo. Fortunately, ncurses provides a pkg-config
file which we can use if pkg-config is installed. If it is not, we still
link to -lncurses for now, so pkg-config is not a hard requirement.
Reported-by: jan.paesmans@gmail.com
X-Gentoo-Bug: 455912
X-Gentoo-Bug: https://bugs.gentoo.org/show_bug.cgi?id=455912
This allows error checking inside the included files instead of either
including the appropriate file or a blank file.
Also the blank file named .mk gets removed by this change.
