If config.cfg is executable, we execute it and accept its output as extra arguments. This makes dynamic configuration possible.

helpers/lh_config

@@ -714,13 +714,16 @@ fi
 # Reading existing configuration
 Read_conffiles config/all config/common config/bootstrap config/chroot config/binary config/source
 
-if [ -e config.cfg ]
+if [ -x config.cfg ]
 then
-	Local_arguments $(cat config.cfg) "${@}"
-else
-	Local_arguments "${@}"
+	EXTRA_ARGUMENTS="./config.cfg"
+elif [ -r config.cfg ]
+then
+	EXTRA_ARGUMENTS="$(cat config.cfg)"
 fi
 
+Local_arguments ${EXTRA_ARGUMENTS} "${@}"
+
 if [ -n "${_CONFFILE}" ]
 then
 	Read_conffiles "${_CONFFILE}"