units: add a service to invoke ldconfig on system updates at boot

Makefile.am

@@ -460,7 +460,8 @@ dist_systemunit_DATA = \
 	units/systemd-udevd-control.socket \
 	units/systemd-udevd-kernel.socket \
 	units/system-update.target \
-	units/initrd-switch-root.target
+	units/initrd-switch-root.target \
+	units/ldconfig.service
 
 nodist_systemunit_DATA = \
 	units/getty@.service \
@@ -5142,7 +5143,8 @@ endif
 
 SYSINIT_TARGET_WANTS += \
 	systemd-update-utmp.service \
-	systemd-update-done.service
+	systemd-update-done.service \
+	ldconfig.service
 
 LOCAL_FS_TARGET_WANTS += \
 	systemd-remount-fs.service \

units/ldconfig.service

@@ -0,0 +1,20 @@
+#  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.
+
+[Unit]
+Description=Rebuild Dynamic Linker Cache
+Documentation=man:ldconfig(8)
+DefaultDependencies=no
+Conflicts=shutdown.target
+After=systemd-readahead-collect.service systemd-readahead-replay.service systemd-remount-fs.service
+Before=sysinit.target shutdown.target systemd-update-done.service
+ConditionNeedsUpdate=/etc
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/sbin/ldconfig -X