include/c: add print_version() macro

include/c: add print_version() macro

Let's consolidate the version printing code. It also seems better to
use exit() after --version, because it's handled in different way by
ASAN.

It's strange, but ASAN reports leaks after return in main(). Note that
we do not use free-before-exit.

Signed-off-by: Karel Zak <kzak@redhat.com>