$ find * -type f |xargs perl contrib/scripts/spdx.pl
  $ git rm contrib/scripts/spdx.pl

Add nm_sd_dns_name_to_wire_format() based on systemd utilities to
convert a name into its wire format according to RFC 1035 section
3.1. It will be used to build the content of the DHCP FQDN option.

Now that unbase64mem_full() understands a secure flag, we can
get this right.

glib has an base64 implementation, but g_base64_decode() et al. gives
no way to detect invalid encodings. All invalid codes are silently
ignored. That is not suitable for strictly validating user input.

Instead of reimplementing of copy-pasting the code from somewhere,
reuse systemd's unbase64mem().

But don't use "hexdecoct.h" directly. Instead, add a single accessor
function to our "nm-sd-utils-shared.h" gateway. We want to be careful
about which bits from systemd we use, because otherwise re-importing
systemd code becomes fragile as you don't know which relevant parts
changed.

For better or worse, we already pull in large parts of systemd sources.

I need a base64 decode implementation (because glib's g_base64_decode()
cannot reject invalid encodings). Instead of coming up with my own or
copy-paste if from somewhere, reuse systemd's unbase64mem().

But for that, make systemd's basic bits an independent static library
first because I will need it in libnm-core.

This doesn't really change anything except making "libnm-systemd-core.la"
an indpendent static library that could be used from "libnm-core". We
shall still be mindful about which internal code of systemd we use, and only
access functionality that is exposed via "systemd/nm-sd-utils-shared.h".