rpmdiff complains about uses of inet_aton, inet_makeaddr, inet_netof,
inet_ntoa under the IPv6 section:

   usr/sbin/NetworkManager on aarch64 i686 x86_64 ppc ppc64 ppc64le s390 s390x uses function inet_aton, which may impact IPv6 support

I think the warning is bogus, but refactor our code to avoid it.

Note that systemd code still uses them, so it don't avoid the rpmdiff
warning. But let's not diverge our systemd import from upstream for this.

- for NMSettingBond:validate_ip() also avoid g_strsplit_set() which
  allocates a full strv. Instead, we can do with one g_strdup().

- for test-resolvconf-capture.c, replace the functions with macros.
  Macros should be avoided usually, but for test asserts they are
  more convenient as they preserved the __FILE__:__LINE__ of where
  the assertion fails.