Change RAND_poll for Unix to try a number of devices and only read
them for a short period of time (actually, poll them with select(),
then read() whatever is there), which is about 10ms (hard-coded value)
each.

Separate Windows and Unixly code, and start on a VMS variant that
currently just returns 0.
diff --git a/CHANGES b/CHANGES
index 0c745b6..8cccebc 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,6 +3,12 @@
 
  Changes between 0.9.6 and 0.9.7  [xx XXX 2000]
 
+  *) Change the Unix RAND_poll() variant to be able to poll several
+     random devices and only read data for a small fragment of time
+     to avoid hangs.  Also separate out the Unix variant to it's own
+     file, rand_unix.c.  For VMS, there's a currently-empty rand_vms.c.
+     [Richard Levitte]
+
   *) Move OCSP client related routines to ocsp_cl.c. These
      provide utility functions which an application needing
      to issue a request to an OCSP responder and analyse the