use NULL to load plugins from default plugin directory

src/scepclient/Makefile.am

@@ -17,7 +17,6 @@ INCLUDES = \
 
 AM_CFLAGS = \
 -DIPSEC_CONFDIR=\"${sysconfdir}\" \
--DIPSEC_PLUGINDIR=\"${plugindir}\" \
 -DPLUGINS=\""${pluto_plugins}\"" \
 -DSTRONGSWAN_CONF=\"${strongswan_conf}\" \
 -DDEBUG -DNO_PLUTO

src/scepclient/scepclient.c

@@ -759,7 +759,7 @@ int main(int argc, char **argv)
 	init_log("scepclient");
 
 	/* load plugins, further infrastructure may need it */
-	if (!lib->plugins->load(lib->plugins, IPSEC_PLUGINDIR,
+	if (!lib->plugins->load(lib->plugins, NULL,
 			lib->settings->get_str(lib->settings, "scepclient.load", PLUGINS)))
 	{
 		exit_scepclient("plugin loading failed");