package/squid: add optional systemd dependency

systemd is an optional dependency (enabled by default) since version
4.11 and
https://github.com/squid-cache/squid/commit/6fa8c66435d55a2e713db0222cdca3a9dccf5bbe

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit a70bcb531ce5e22e8a6126a6ed774dd538e18623)
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/squid/squid.mk

@@ -62,6 +62,13 @@ else
 SQUID_CONF_OPTS += --without-gnutls
 endif
 
+ifeq ($(BR2_PACKAGE_SYSTEMD),y)
+SQUID_CONF_OPTS += --with-systemd
+SQUID_DEPENDENCIES += systemd
+else
+SQUID_CONF_OPTS += --without-systemd
+endif
+
 define SQUID_CLEANUP_TARGET
 	rm -f $(addprefix $(TARGET_DIR)/usr/bin/, \
 		RunCache RunAccel)