daemon+tests: avoid deprecated ndn-cxx functions

Change-Id: Idfa341629919d63fac140eda0b465f8f8abd38e6
diff --git a/wscript b/wscript
index afec2fc..b08fbf6 100644
--- a/wscript
+++ b/wscript
@@ -94,8 +94,9 @@
     conf.find_program('bash', var='BASH')
     conf.find_program('dot', var='DOT', mandatory=False)
 
-    conf.check_cfg(package='libndn-cxx', args=['--cflags', '--libs'], uselib_store='NDN_CXX',
-                   pkg_config_path=os.environ.get('PKG_CONFIG_PATH', '%s/pkgconfig' % conf.env.LIBDIR))
+    pkg_config_path = os.environ.get('PKG_CONFIG_PATH', f'{conf.env.LIBDIR}/pkgconfig')
+    conf.check_cfg(package='libndn-cxx', args=['libndn-cxx >= 0.8.0', '--cflags', '--libs'],
+                   uselib_store='NDN_CXX', pkg_config_path=pkg_config_path)
 
     if not conf.options.without_systemd:
         conf.check_cfg(package='libsystemd', args=['--cflags', '--libs'],