games/golly: Fix build on aarch64 or when objdump is missing

Golly dlopens Python at runtime and looks up its shared library
name during configure. It first tries to do this using
distutils.sysconfig.get_config_var("LDLIBRARY"), and then tries to
use objdump if that fails. Since the former is unlikely to ever
fail on FreeBSD, objdump will never actually be called and we can
pacify configure by pretending objdump is available.