It suddenly strikes me as probably a good idea to enforce that anyone

calling random_byte has previously called random_ref.

(I'm not aware of any current code getting this wrong! It just seems
to me to be the sort of thing you'd want to be really sure of.)

[originally from svn r9930]

sshrand.c

@@ -234,6 +234,8 @@ void random_unref(void)
 
 int random_byte(void)
 {
+    assert(random_active);
+
     if (pool.poolpos >= POOLSIZE)
 	random_stir();