Implement internBytes by intern
diff --git a/symtab.go b/symtab.go
index 69b0b43..c162535 100644
--- a/symtab.go
+++ b/symtab.go
@@ -11,10 +11,5 @@
 }
 
 func internBytes(s []byte) string {
-	if v, ok := symtab[string(s)]; ok {
-		return v
-	}
-	v := string(s)
-	symtab[v] = v
-	return v
+	return intern(string(s))
 }