getty: support /run/issue.d/

By default agetty will not display /run/issue.d/ if /etc/issue exists.
This is quite unfortunate and has actually been fixed upstream in:

https://github.com/util-linux/util-linux/commit/508fb0e7ac103b68531a59db2a4473897853ab52

However, no release has been tagged with this yet, and it doesn't look
like this will happen any time soon. Hence, for now, let's add a
work-around and manually override the issue files to include.

This should be reverted once a new util-linux/agetty release has been
tagged, and found its way into the relevant distributions. Given this is
mostly about cosmetics we do not have to precisely sync the package
updates on this, but only roughly.

TODO

@@ -118,6 +118,10 @@ Deprecations and removals:
 
 * Consider removing root=gpt-auto, and push people to use root=dissect instead.
 
+* Once
+  https://github.com/util-linux/util-linux/commit/508fb0e7ac103b68531a59db2a4473897853ab52
+  has hit the prominent distributions, revert --issue-file= hack in units/*getty*sevice.in
+
 Features:
 
 * replace bootctl's PE version check to actually use APIs from pe-binary.[ch]

units/console-getty.service.in

@@ -20,7 +20,7 @@ Before=getty.target
 ConditionPathExists=/dev/console
 
 [Service]
-ExecStart=-/sbin/agetty --noreset --noclear --keep-baud 115200,57600,38400,9600 - ${TERM}
+ExecStart=-/sbin/agetty --noreset --noclear --issue-file=/etc/issue:/etc/issue.d:/run/issue.d:/usr/lib/issue.d --keep-baud 115200,57600,38400,9600 - ${TERM}
 Type=idle
 Restart=always
 UtmpIdentifier=cons

units/container-getty@.service.in

@@ -25,7 +25,7 @@ Conflicts=rescue.service
 Before=rescue.service
 
 [Service]
-ExecStart=-/sbin/agetty --noreset --noclear - ${TERM}
+ExecStart=-/sbin/agetty --noreset --noclear --issue-file=/etc/issue:/etc/issue.d:/run/issue.d:/usr/lib/issue.d - ${TERM}
 Type=idle
 Restart=always
 RestartSec=0

units/getty@.service.in

@@ -34,7 +34,7 @@ Before=rescue.service
 ConditionPathExists=/dev/tty0
 
 [Service]
-ExecStart=-/sbin/agetty --noreset --noclear - ${TERM}
+ExecStart=-/sbin/agetty --noreset --noclear --issue-file=/etc/issue:/etc/issue.d:/run/issue.d:/usr/lib/issue.d - ${TERM}
 Type=idle
 Restart=always
 RestartSec=0

units/serial-getty@.service.in

@@ -30,7 +30,7 @@ Conflicts=rescue.service
 Before=rescue.service
 
 [Service]
-ExecStart=-/sbin/agetty --noreset --noclear --keep-baud 115200,57600,38400,9600 - ${TERM}
+ExecStart=-/sbin/agetty --noreset --noclear --issue-file=/etc/issue:/etc/issue.d:/run/issue.d:/usr/lib/issue.d --keep-baud 115200,57600,38400,9600 - ${TERM}
 Type=idle
 Restart=always
 UtmpIdentifier=%I