systemd: Make the log persistent for the IDU

Similar to the T-ODU we would like to keep a persistent log.
This commit is completely untested, rushed and not the final
one (/etc/default/volatiles/00_core most likely needs patching
and we want to limit the size of the log as well).

Related: SYS#659

recipes-fixes/systemd/systemd/sysmocom-idu/journald.conf

@@ -0,0 +1,34 @@
+#  This file is part of systemd.
+#
+#  systemd is free software; you can redistribute it and/or modify it
+#  under the terms of the GNU Lesser General Public License as published by
+#  the Free Software Foundation; either version 2.1 of the License, or
+#  (at your option) any later version.
+#
+# See journald.conf(5) for details
+
+# Always use a volatile storage and keep the log size down but more
+# importantly the address space of the journald
+
+[Journal]
+Storage=persistent
+#Compress=yes
+#Seal=no
+#RateLimitInterval=10s
+#RateLimitBurst=200
+#SystemMaxUse=10
+#SystemKeepFree=
+#SystemMaxFileSize=
+#SystemMinFileSize=
+RuntimeMaxUse=648K
+#RuntimeKeepFree=
+#RuntimeMaxFileSize=
+#RuntimeMinFileSize=
+#ForwardToSyslog=yes
+#ForwardToKMsg=no
+#ForwardToConsole=no
+#TTYPath=/dev/console
+#MaxLevelStore=debug
+#MaxLevelSyslog=debug
+#MaxLevelKMsg=notice
+#MaxLevelConsole=info

recipes-fixes/systemd/systemd_sysmocom.inc

@@ -1,7 +1,7 @@
 S_THISDIR := "${@os.path.dirname(bb.data.getVar('FILE', d, True))}"
 FILESPATH =. "${@base_set_filespath(["${S_THISDIR}/${PN}"], d)}:"
 
-PRINC="24"
+PRINC="25"
 
 SRC_URI += "file://journald.conf \
             file://legacy.conf \