Use curl if not running on OpenBSD

bin/rfcopen.sh

@@ -22,6 +22,19 @@ err()
 	exit 1
 }
 
+fetch_file()
+{
+	# Assumes utility supports `-o output_file`
+	case $(uname) in
+	OpenBSD)
+		$torsocks ftp -MV "$@"
+		;;
+	*)
+		$torsocks curl -fLSs "$@"
+		;;
+	esac
+}
+
 tonumber()
 {
 	printf "%u" "$1" 2>/dev/null
@@ -44,6 +57,6 @@ url=https://tools.ietf.org/rfc/rfc$n.txt
 
 mkdir -p "$RFCDIR"
 if [ ! -f "$rfcfile" ]; then
-	$torsocks ftp -Vo "$rfcfile" "$url" || err "couldn't fetch RFC $n"
+	fetch_file -o "$rfcfile" "$url" || err "couldn't fetch RFC $n"
 fi
 ${PAGER:-more} "$rfcfile"