Pull in go-flags, modified to build on Solaris

github.com/jessevdk/go-flags/closest.go

@@ -0,0 +1,61 @@
+package flags
+
+func levenshtein(s string, t string) int {
+	if len(s) == 0 {
+		return len(t)
+	}
+
+	if len(t) == 0 {
+		return len(s)
+	}
+
+	var l1, l2, l3 int
+
+	if len(s) == 1 {
+		l1 = len(t) + 1
+	} else {
+		l1 = levenshtein(s[1:len(s)-1], t) + 1
+	}
+
+	if len(t) == 1 {
+		l2 = len(s) + 1
+	} else {
+		l2 = levenshtein(t[1:len(t)-1], s) + 1
+	}
+
+	l3 = levenshtein(s[1:len(s)], t[1:len(t)])
+
+	if s[0] != t[0] {
+		l3 += 1
+	}
+
+	if l2 < l1 {
+		l1 = l2
+	}
+
+	if l1 < l3 {
+		return l1
+	}
+
+	return l3
+}
+
+func closestChoice(cmd string, choices []string) (string, int) {
+	if len(choices) == 0 {
+		return "", 0
+	}
+
+	mincmd := -1
+	mindist := -1
+
+	for i, c := range choices {
+		l := levenshtein(cmd, c)
+
+		if mincmd < 0 || l < mindist {
+			mindist = l
+			mincmd = i
+		}
+	}
+
+	return choices[mincmd], mindist
+}