Note the "ex_data" changes.

         *) applies to 0.9.6a/0.9.6b/0.9.6c and 0.9.7

         *) applies to 0.9.6a/0.9.6b/0.9.6c and 0.9.7

         +) applies to 0.9.7 only

         +) applies to 0.9.7 only

  +) As with "ERR", make it possible to replace the underlying "ex_data"

     functions. This change also alters the storage and management of global

     ex_data state - it's now all inside ex_data.c and all "class" code (eg.

     RSA, BIO, SSL_CTX, etc) no longer stores its own STACKS and per-class

     index counters. The API functions that use this state have been changed

     to take a "class_index" rather than pointers to the class's local STACK

     and counter, and there is now an API function to dynamically create new

     classes. This centralisation allows us to (a) plug a lot of the

     thread-safety problems that existed, and (b) makes it possible to clean

     up all allocated state using "CRYPTO_cleanup_all_ex_data()". W.r.t. (b)

     such data would previously have always leaked in application code and

     workarounds were in place to make the memory debugging turn a blind eye

     to it. Application code that doesn't use this new function will still

     leak as before, but their memory debugging output will announce it now

     rather than letting it slide.

     [Geoff Thorpe]

  +) Make it possible to replace the underlying "ERR" functions such that the

  +) Make it possible to replace the underlying "ERR" functions such that the

     global state (2 LHASH tables and 2 locks) is only used by the "default"

     global state (2 LHASH tables and 2 locks) is only used by the "default"

     implementation. This change also adds two functions to "get" and "set"

     implementation. This change also adds two functions to "get" and "set"