Along with the accompanying change to gpgme to install gpgme-config,
since libfko is what is actually linked to gpgme, and not
fwknop/fwknopd, an explicit dependency must be added to that package.

menuconfig now allows enabling gpg support if only fwknop is selected
without also selecting fwknopd.

Signed-off-by: Matt Merhar <mattmerhar@protonmail.com>