systemd: Add 'no-dns-fallback' PACKAGECONFIG option

systemd defines a default set of fallback DNS servers in
https://github.com/systemd/systemd/blob/v251/meson_options.txt#L328-L330

By adding a PACKAGECONFIG knob providing a convenient way to opt out,
and then adding that value to systemd's PACKAGECONFIG, the output from
runtime 'resolvectl status' command no longer contains the following
line:

  Fallback DNS Servers: 1.1.1.1#cloudflare-dns.com 8.8.8.8#dns.google 1.0.0.1#cloudflare-dns.com 8.8.4.4#dns.google 2606:4700:4700::1111#cloudflare-dns.com 2001:4860:4860::8888#dns.google 2606:4700:4700::1001#cloudflare-dns.com 2001:4860:4860::8844#dns.google

(From OE-Core rev: 2b300d6b9ec6288a99d9dacb24a86949caf99e55)

(From OE-Core rev: 834ccad676b3d8d58d1a66bbe813a331599435b4)

Signed-off-by: Niko Mauno <niko.mauno@vaisala.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/meta/recipes-core/systemd/systemd_244.5.bb b/meta/recipes-core/systemd/systemd_244.5.bb
index a648272bc0..f3e5395465 100644
--- a/meta/recipes-core/systemd/systemd_244.5.bb
+++ b/meta/recipes-core/systemd/systemd_244.5.bb
@@ -162,6 +162,7 @@ PACKAGECONFIG[manpages] = "-Dman=true,-Dman=false,libxslt-native xmlto-native do
 PACKAGECONFIG[microhttpd] = "-Dmicrohttpd=true,-Dmicrohttpd=false,libmicrohttpd"
 PACKAGECONFIG[myhostname] = "-Dnss-myhostname=true,-Dnss-myhostname=false,,libnss-myhostname"
 PACKAGECONFIG[networkd] = "-Dnetworkd=true,-Dnetworkd=false"
+PACKAGECONFIG[no-dns-fallback] = "-Ddns-servers="
 PACKAGECONFIG[nss] = "-Dnss-systemd=true,-Dnss-systemd=false"
 PACKAGECONFIG[nss-mymachines] = "-Dnss-mymachines=true,-Dnss-mymachines=false"
 PACKAGECONFIG[nss-resolve] = "-Dnss-resolve=true,-Dnss-resolve=false"