If the systemd service file is not installed, currently the related man-page
and example nft file are still installed.  Instead only install them when the
service file is installed.

Fixes: 107580cfa85c ("build: disable --with-unitdir by default")
Signed-off-by: Jeremy Sowden <jeremy@azazel.net>
---
 Makefile.am  | 5 +++++
 configure.ac | 1 +
 2 files changed, 6 insertions(+)

diff --git a/Makefile.am b/Makefile.am
index fac7ad55cbe7..bf1c3c443d40 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -421,10 +421,14 @@ EXTRA_DIST += \
 	tools/nftables.service.in \
 	$(NULL)
 
+if BUILD_SERVICE
 CLEANFILES += tools/nftables.service
+endif
 
 pkgconfigdir = $(libdir)/pkgconfig
 pkgconfig_DATA = libnftables.pc
+
+if BUILD_SERVICE
 unit_DATA = tools/nftables.service
 man_MANS = tools/nftables.service.8
 doc_DATA = files/nftables/main.nft
@@ -432,6 +436,7 @@ doc_DATA = files/nftables/main.nft
 tools/nftables.service: tools/nftables.service.in ${top_builddir}/config.status
 	${AM_V_GEN}${MKDIR_P} tools
 	${AM_V_at}sed -e 's|@''sbindir''@|${sbindir}|g;s|@''pkgsysconfdir''@|${pkgsysconfdir}|g' <${srcdir}/tools/nftables.service.in >$@
+endif
 
 if !BUILD_DISTCHECK
 TESTS = tests/build/run-tests.sh \
diff --git a/configure.ac b/configure.ac
index a3ae2956cdf3..f3f6ad436bed 100644
--- a/configure.ac
+++ b/configure.ac
@@ -130,6 +130,7 @@ AC_ARG_WITH([unitdir],
 	[unitdir=""]
 )
 AC_SUBST([unitdir])
+AM_CONDITIONAL([BUILD_SERVICE], [test "x$unitdir" != x])
 
 AC_ARG_WITH([stable-release], [AS_HELP_STRING([--with-stable-release],
             [Stable release number])],
-- 
2.51.0