+TL/02 The BSD's have an arc4random API. One of the functions to induce
+ adding randomness was arc4random_stir(), but it has been removed in
+ OpenBSD 5.5. Detect this OpenBSD version and skip calling this
+ function when detected.
+
+JH/01 Expand the EXPERIMENTAL_TPDA feature. Several different events now
+ cause callback expansion.
+