release: Configure default SYSTEMD_NETLINK_DEFAULT_TIMEOUT

Write a drop-in for the systemd-networkd service that sets the
SYSTEMD_NETLINK_DEFAULT_TIMEOUT environment variable to "infinity",
rather than use the default timeout of 25 seconds.  This ensures that
systemd-networkd won't put links into an inoperable state if the
kernel/system is heavily loaded and doesn't respond right away.

packages/release/release.spec

@@ -75,6 +75,7 @@ Source1080: runtime.slice
 # Drop-in units to override defaults
 Source1100: systemd-tmpfiles-setup-service-debug.conf
 Source1101: systemd-resolved-service-env.conf
+Source1102: systemd-networkd-service-env.conf
 
 # systemd-udevd default link
 Source1200: 80-release.link
@@ -167,6 +168,10 @@ install -d %{buildroot}%{_cross_unitdir}/systemd-resolved.service.d
 install -p -m 0644 %{S:1101} \
   %{buildroot}%{_cross_unitdir}/systemd-resolved.service.d/00-env.conf
 
+install -d %{buildroot}%{_cross_unitdir}/systemd-networkd.service.d
+install -p -m 0644 %{S:1102} \
+  %{buildroot}%{_cross_unitdir}/systemd-networkd.service.d/00-env.conf
+
 LOWERPATH=$(systemd-escape --path %{_cross_sharedstatedir}/kernel-devel/.overlay/lower)
 sed -e 's|PREFIX|%{_cross_prefix}|' %{S:1020} > ${LOWERPATH}.mount
 install -p -m 0644 ${LOWERPATH}.mount %{buildroot}%{_cross_unitdir}
@@ -251,6 +256,8 @@ ln -s preconfigured.target %{buildroot}%{_cross_unitdir}/default.target
 %{_cross_unitdir}/[email protected]
 %dir %{_cross_unitdir}/systemd-resolved.service.d
 %{_cross_unitdir}/systemd-resolved.service.d/00-env.conf
+%dir %{_cross_unitdir}/systemd-networkd.service.d
+%{_cross_unitdir}/systemd-networkd.service.d/00-env.conf
 %dir %{_cross_unitdir}/systemd-tmpfiles-setup.service.d
 %{_cross_unitdir}/systemd-tmpfiles-setup.service.d/00-debug.conf
 %dir %{_cross_templatedir}

packages/release/systemd-networkd-service-env.conf

@@ -0,0 +1,2 @@
+[Service]
+Environment=SYSTEMD_NETLINK_DEFAULT_TIMEOUT=infinity