typedef const char *struniq_t;
/* Return the struniq for S. */
-const struniq_t struniq_new (const char *s);
+struniq_t struniq_new (const char *s);
/* Two struniq have the same value iff they are the same. */
#define STRUNIQ_EQ(S1, S2) ((S1) == (S2))