Some more const string fixes.
diff --git a/lib/sockunion.h b/lib/sockunion.h
index 99bdf6a..92e536c 100644
--- a/lib/sockunion.h
+++ b/lib/sockunion.h
@@ -87,7 +87,7 @@
#define sockunion_family(X) (X)->sa.sa_family
/* Prototypes. */
-int str2sockunion (char *, union sockunion *);
+int str2sockunion (const char *, union sockunion *);
const char *sockunion2str (union sockunion *, char *, size_t);
int sockunion_cmp (union sockunion *, union sockunion *);
int sockunion_same (union sockunion *, union sockunion *);