-SBINDIR=${DESTDIR}/usr/sbin
-MAN8DIR=${DESTDIR}/usr/share/man/man8
-DOCDIR=${DESTDIR}/usr/share/doc/${PACKAGE}
-WORKDIR=${DESTDIR}/var/lib/pve-zsync
+SBINDIR=$(DESTDIR)/usr/sbin
+MAN8DIR=$(DESTDIR)/usr/share/man/man8
+DOCDIR=$(DESTDIR)/usr/share/doc/$(PACKAGE)
+WORKDIR=$(DESTDIR)/var/lib/pve-zsync