sysusers: split up default sysusers snippet

This ways, distributions have an easier way to replace the OS specific
generic groups/users while keeping systemd's own.

Makefile.am

@@ -1846,15 +1846,18 @@ nodist_systemunit_DATA += \
 SYSINIT_TARGET_WANTS += \
 	systemd-sysusers.service
 
-nodist_sysusers_DATA = \
+dist_sysusers_DATA = \
 	sysusers.d/systemd.conf
 
+nodist_sysusers_DATA = \
+	sysusers.d/basic.conf
+
 EXTRA_DIST += \
 	units/systemd-sysusers.service.in \
-	sysusers.d/systemd.conf.in
+	sysusers.d/basic.conf.in
 
 CLEANFILES += \
-	sysusers.d/systemd.conf
+	sysusers.d/basic.conf
 
 INSTALL_DIRS += \
 	$(sysusersdir)

sysusers.d/.gitignore

@@ -1 +1 @@
-/systemd.conf
+/basic.conf

sysusers.d/basic.conf.in

@@ -35,11 +35,3 @@ g video                         -               -
 
 # Default group for normal users
 g users                         -               -
-
-# Users and groups for specific systemd subsystems
-g systemd-journal               -               -
-u systemd-journal-gateway       -               "systemd Journal Gateway"
-u systemd-bus-proxy             -               "systemd Bus Proxy"
-u systemd-network               -               "systemd Network Management"
-u systemd-resolve               -               "systemd Resolver"
-u systemd-timesync              -               "systemd Time Synchronization"

sysusers.d/systemd.conf

@@ -0,0 +1,13 @@
+#  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.
+
+g systemd-journal               -               -
+u systemd-journal-gateway       -               "systemd Journal Gateway"
+u systemd-bus-proxy             -               "systemd Bus Proxy"
+u systemd-network               -               "systemd Network Management"
+u systemd-resolve               -               "systemd Resolver"
+u systemd-timesync              -               "systemd Time Synchronization"