meson: factor out daemon/event/id128 sources into variables (#8170)

src/libsystemd/meson.build

@@ -15,6 +15,14 @@
 # You should have received a copy of the GNU Lesser General Public License
 # along with systemd; If not, see <http://www.gnu.org/licenses/>.
 
+id128_sources = files('''
+        sd-id128/id128-util.c
+        sd-id128/id128-util.h
+        sd-id128/sd-id128.c
+'''.split())
+
+sd_daemon_c = files('sd-daemon/sd-daemon.c')
+sd_event_c = files('sd-event/sd-event.c')
 sd_login_c = files('sd-login/sd-login.c')
 
 libsystemd_sources = files('''
@@ -57,7 +65,6 @@ libsystemd_sources = files('''
         sd-bus/bus-type.c
         sd-bus/bus-type.h
         sd-bus/sd-bus.c
-        sd-daemon/sd-daemon.c
         sd-device/device-enumerator-private.h
         sd-device/device-enumerator.c
         sd-device/device-internal.h
@@ -65,13 +72,9 @@ libsystemd_sources = files('''
         sd-device/device-private.h
         sd-device/device-util.h
         sd-device/sd-device.c
-        sd-event/sd-event.c
         sd-hwdb/hwdb-internal.h
         sd-hwdb/hwdb-util.h
         sd-hwdb/sd-hwdb.c
-        sd-id128/id128-util.c
-        sd-id128/id128-util.h
-        sd-id128/sd-id128.c
         sd-netlink/generic-netlink.c
         sd-netlink/local-addresses.c
         sd-netlink/local-addresses.h
@@ -90,7 +93,7 @@ libsystemd_sources = files('''
         sd-path/sd-path.c
         sd-resolve/sd-resolve.c
         sd-utf8/sd-utf8.c
-'''.split()) + sd_login_c
+'''.split()) + id128_sources + sd_daemon_c + sd_event_c + sd_login_c
 
 libsystemd_static = static_library(
         'systemd',