tools: Drop libsystemd as a dependency

There are no more users, and we want to disuade people from introducing new
users just for sd_notify() and friends.  Drop the dependency.

We still want the overall --with{,out}-systemd to gate the generation of the
service/unit/mount/etc files.

Rerun autogen.sh, and mark the dependency as removed in the build containers.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Christian Lindig <christian.lindig@cloud.com>

config/Tools.mk.in

@@ -52,8 +52,6 @@ CONFIG_PYGRUB       := @pygrub@
 CONFIG_LIBFSIMAGE   := @libfsimage@
 
 CONFIG_SYSTEMD      := @systemd@
-SYSTEMD_CFLAGS      := @SYSTEMD_CFLAGS@
-SYSTEMD_LIBS        := @SYSTEMD_LIBS@
 XEN_SYSTEMD_DIR     := @SYSTEMD_DIR@
 XEN_SYSTEMD_MODULES_LOAD := @SYSTEMD_MODULES_LOAD@
 CONFIG_9PFS         := @ninepfs@