With earlier meson versions (pre 0.50) build_by_default and install
didn't have great integration. With newer meson versions, as the former
is undefined the latter will control both.
More importantly, the whole meson.build is included only on
get_option('manpages').
Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com> Reviewed-by: Lucas De Marchi <demarchi@kernel.org> Link: https://github.com/kmod-project/kmod/pull/pull/400 Signed-off-by: Lucas De Marchi <demarchi@kernel.org>