Modernize spec to recent changes

Add dhcpcd user on installation, make local state directory writable by
it.

dhcpcd.spec

@@ -12,8 +12,9 @@ Source1: %{name}.service
 Source2: %{name}@.service
 Source3: http://roy.marples.name/downloads/%{name}/%{name}-%{version}.tar.xz.distinfo.asc
 Source4: http://keys.gnupg.net/pks/lookup?op=get&search=0x597F97EA9AD45549&options=mr#/roy-marples.name.asc
-BuildRequires:  gcc
-BuildRequires: systemd
+Source5: systemd-sysusers.conf
+BuildRequires: gcc
+BuildRequires: systemd-rpm-macros
 BuildRequires: chrony
 BuildRequires: systemd-devel
 BuildRequires: ypbind
@@ -21,9 +22,7 @@ BuildRequires: make
 %if %{with SIGCHECK}
 BuildRequires: gnupg2
 %endif
-Requires(post): systemd
-Requires(preun): systemd
-Requires(postun): systemd
+%{?systemd_requires}
 %description
 The dhcpcd package provides a minimalistic network configuration daemon
 that supports IPv4 and IPv6 configuration including configuration discovery
@@ -55,14 +54,17 @@ install -D -m 644 %{SOURCE1} %{buildroot}%{_unitdir}/%{name}.service
 install -D -m 644 %{SOURCE2} %{buildroot}%{_unitdir}/%{name}@.service
 install -d %{buildroot}%{_sharedstatedir}/%{_name}
 
+%pre
+%sysusers_create_compat %{SOURCE5}
+
 %post
-%systemd_post dhcpcd.service
+%systemd_post %{name}.service
 
 %preun
-%systemd_preun dhcpcd.service
+%systemd_preun %{name}.service
 
 %postun
-%systemd_postun_with_restart dhcpcd.service
+%systemd_postun_with_restart %{name}.service
 
 %files
 %config(noreplace) %{_sysconfdir}/%{name}.conf
@@ -79,6 +81,7 @@ install -d %{buildroot}%{_sharedstatedir}/%{_name}
 %{_sbindir}/%{name}
 %{_unitdir}/%{name}.service
 %{_unitdir}/%{name}@.service
+%defattr(0664,dhcpcd,root,0775)
 %{_sharedstatedir}/%{name}
 
 %changelog

dhcpcd@.service

@@ -2,12 +2,10 @@
 Description=dhcpcd on %I
 Wants=network.target
 Before=network.target
-BindsTo=sys-subsystem-net-devices-%i.device
-After=sys-subsystem-net-devices-%i.device
 
 [Service]
 Type=forking
-PIDFile=/run/dhcpcd-%I.pid
+PIDFile=/run/dhcpcd/%I.pid
 ExecStart=/usr/sbin/dhcpcd -q %I
 ExecStop=/usr/sbin/dhcpcd -x %I
 

systemd-sysusers.conf

@@ -0,0 +1 @@
+u dhcpcd - "Minimalistic DHCP client" /var/lib/dhcpcd