scstadmin.spec: Install unit into %{_unitdir} and package it

Fixes: https://github.com/SCST-project/scst/issues/323

scstadmin/Makefile

@@ -33,6 +33,7 @@ INITDIR := $(shell if [ -f /etc/slackware-version ]; then	\
                    else						\
                      echo /etc/init.d;				\
                    fi)
+SYSTEMD_UNITDIR ?= /lib/systemd/system
 
 ECHO_INSTALL_FN =							\
 	if [ -n "$(DESTDIR)" ]; then					\
@@ -112,9 +113,9 @@ install install_vendor:
 	fi
 	# Install systemd service file
 	if [ -d systemd ]; then						\
-	  install -d $(DESTDIR)/lib/systemd/system;			\
+	  install -d $(DESTDIR)$(SYSTEMD_UNITDIR);			\
 	  install -m 644 systemd/scst.service				\
-	    $(DESTDIR)/lib/systemd/system/scst.service;			\
+	    $(DESTDIR)$(SYSTEMD_UNITDIR)/scst.service;			\
 	fi
 	for s in iscsi-scst qla2x00t; do			\
 	  { $(call REMOVE_FN,$$s); } >/dev/null 2>&1;		\

scstadmin/scstadmin.spec.in

@@ -17,6 +17,8 @@ Source:		%{name}-%{version}.tar.bz2
 BuildRoot:	%{_tmppath}/%{name}-%{version}-build
 AutoReqProv:	yes
 Requires:	psmisc, coreutils
+BuildRequires:	systemd-rpm-macros
+%{?systemd_requires}
 
 %description
 A tool for configuring SCST via the SCST sysfs interface. Allows to save,
@@ -56,7 +58,7 @@ export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir}
 %{make}
 
 %install
-export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir} SBINDIR=%{_sbindir}
+export PREFIX=%{_prefix} DESTDIR=%{buildroot} MANDIR=%{buildroot}%{_mandir} SBINDIR=%{_sbindir} SYSTEMD_UNITDIR=%{_unitdir}
 %{make} install_vendor
 %scstadmin_perl_process_packlist
 rm -rf %{buildroot}/var/adm/perl-modules/scst
@@ -71,10 +73,20 @@ rm -f /usr/local/man/man3/SCST::SCST.3pm*
 rm -f /usr/local/man/man5/scst.5*
 rm -f /usr/local/man/man5/scst.conf.5*
 
+%post
+%systemd_post scst.service
+
+%preun
+%systemd_preun scst.service
+
+%postun
+%systemd_postun scst.service
+
 %files
 %defattr(-,root,root,0755)
 %config(noreplace) /etc/default/scst
 /etc/init.d/scst
+%{_unitdir}/scst.service
 %{_sbindir}/scstadmin
 %{perl_vendorlib}/SCST
 %{perl_vendorarch}/auto/SCST_SCST