tools/xenstore: Cleanup makefile

tools/xenstore: Cleanup makefile

Regroup *FLAGS together, use $(LDLIBS).

Remove $(LDLIBS_xenstored) which was the wrong name name as it doesn't
decribe how to link to a potential libxenstored.so, instead add the
value to $(LDLIBS) of xenstored.

Add SYSTEMD_LIBS into $(LDLIBS) instead of $(LDFLAGS).

Remove the "-I." from $(CFLAGS), it shouldn't be needed.

Removed $(CFLAGS-y) and $(LDFLAGS-y). $(CFLAGS-y) is already included
in $(CFLAGS) and both aren't used anyway.

Rename ALL_TARGETS to TARGETS.
Only add programmes we want to build in $(TARGETS), not phony-targets
(replace "clients").

Store all `xenstored` objs into $(XENSTORED_OBJS-y).

Replace one $< by $^ even if there's only one dependency,
(xenstore-control).

clean: "init-xenstore-domain" isn't built here any more, so stop
trying to remove it, remove $(TARGETS). Also regroup all files to be
removed in one command, using $(RM).

Drop $(MAJOR) and $(MINOR), they aren't used anymore.

Drop ".SECONDARY:", it doesn't appear there's intermediate files that
would be deleted anymore.

Drop "tarball:" target.

Signed-off-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Juergen Gross <jgross@suse.com>