+ *) To cater for systems that provide a pointer-based thread ID rather
+ than numeric, deprecate the current numeric thread ID mechanism and
+ replace it with a structure and associated callback type. This
+ mechanism allows a numeric "hash" to be extracted from a thread ID in
+ either case, and on platforms where pointers are larger than 'long',
+ mixing is done to help ensure the numeric 'hash' is usable even if it
+ can't be guaranteed unique. The default mechanism is to use "&errno"
+ as a pointer-based thread ID to distinguish between threads.
+
+ Applications that want to provide their own thread IDs should now use
+ CRYPTO_THREADID_set_callback() to register a callback that will call
+ either CRYPTO_THREADID_set_numeric() or CRYPTO_THREADID_set_pointer().
+
+ Note that ERR_remove_state() is now deprecated, because it is tied
+ to the assumption that thread IDs are numeric. ERR_remove_state(0)
+ to free the current thread's error state should be replaced by
+ ERR_remove_thread_state(NULL).
+
+ (This new approach replaces the functions CRYPTO_set_idptr_callback(),
+ CRYPTO_get_idptr_callback(), and CRYPTO_thread_idptr() that existed in
+ OpenSSL 0.9.9-dev between June 2006 and August 2008. Also, if an
+ application was previously providing a numeric thread callback that
+ was inappropriate for distinguishing threads, then uniqueness might
+ have been obtained with &errno that happened immediately in the
+ intermediate development versions of OpenSSL; this is no longer the
+ case, the numeric thread callback will now override the automatic use
+ of &errno.)
+ [Geoff Thorpe, with help from Bodo Moeller]
+
+ *) Initial support for different CRL issuing certificates. This covers a
+ simple case where the self issued certificates in the chain exist and
+ the real CRL issuer is higher in the existing chain.