systemd: Install also the unit configuration files

If SYSTEMDSYSTEMUNITDIR is defined, the systemd units are automatically
installed. Therefore consequently also install the required config files
in that case.

Example:

 $ make install SYSTEMDSYSTEMUNITDIR=/usr/lib/systemd/system/

Reviewed-by: Benjamin Block <bblock@linux.vnet.ibm.com>
Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>

etc/Makefile

@@ -0,0 +1,16 @@
+include ../common.mak
+
+CONFIG_FILES =
+
+ifneq (${SYSTEMDSYSTEMUNITDIR},)
+CONFIG_FILES += cpuplugd.conf sysconfig/cpi sysconfig/dumpconf \
+                sysconfig/mon_fsstatd sysconfig/mon_procd
+endif
+
+install:
+	for file in $(CONFIG_FILES); do \
+		$(INSTALL) -g $(GROUP) -o $(OWNER) \
+			   -m 644 $$file $(DESTDIR)$(SYSCONFDIR)/$$file ; \
+	done
+
+.PHONY: all install clean