target() {
	if [ $# -lt 1 ]
	then
		echo "target setting: required argument missing" 1>&2
		exit 1
	fi
	if [ -n "$TARGET" ]
	then
		echo "Error: target specified more than once" 1>&2
		exit 1
	fi
	if [ ! -f "cfgmagic/target.$1" ]
	then
		echo "Error: target $1 not known" 1>&2
		exit 1
	fi
	# looks good, proceed
	TARGET="$1"
	. "cfgmagic/target.$1"
	. cfgmagic/post-target
}

feature() {
	if [ $# -lt 1 ]
	then
		echo "feature setting: required argument missing" 1>&2
		exit 1
	fi
	if [ -z "$TARGET" ]
	then
		echo "Please specify the target before any features" 1>&2
		exit 1
	fi
	if [ ! -f "cfgmagic/feature.$1" ]
	then
		echo "Error: feature $1 not known" 1>&2
		exit 1
	fi
	# looks good, proceed
	. "cfgmagic/feature.$1"
}

export_to_c() {
	if [ $# != 1 ]
	then
		echo "export_to_c: wrong number of arguments" 1>&2
		exit 1
	fi
	case "$c_export_list" in
		*" $1 "* | *" $1")
			;;
		*)
			c_export_list="$c_export_list $1"
			;;
	esac
}

export_to_mk() {
	if [ $# != 1 ]
	then
		echo "export_to_mk: wrong number of arguments" 1>&2
		exit 1
	fi
	case "$mk_export_list" in
		*" $1 "* | *" $1")
			;;
		*)
			mk_export_list="$mk_export_list $1"
			;;
	esac
}

export_to_m4() {
	if [ $# != 1 ]
	then
		echo "export_to_m4: wrong number of arguments" 1>&2
		exit 1
	fi
	case "$m4_export_list" in
		*" $1 "* | *" $1")
			;;
		*)
			m4_export_list="$m4_export_list $1"
			;;
	esac
}