// caller responsible for key storage, no copies made (don't free it b4 xht_free()!)
// set val to NULL to clear an entry, memory is reused but never free'd (# of keys only grows to peak usage)
-void xht_set(xht h, const char *key, void *val);
+void xht_set(xht h, char *key, void *val);
// ooh! unlike set where key/val is in caller's mem, here they are copied into xht and free'd when val is 0 or xht_free()
void xht_store(xht h, const char *key, int klen, void *val, int vlen);