This is done by splitting variables.errmsg and locale.errmsg to
variables.errmsg_extra and locale.errmsg_extra
The ER() macros in unireg.h now looks more complex than before, but this
isn't critical as most usage of them are with constants and the compiler
will remove most of the test code.
--encrypt-binlog and --encrypt-tmp-files used to mean
"encrypt XXX if encryption is available, otherwise don't encrypt",
now they mean "encrypt or fail with an error".
Instead of encrypt(src, dst, key, iv) that encrypts all
data in one go, now we have encrypt_init(key,iv),
encrypt_update(src,dst), and encrypt_finish(dst).
This also causes collateral changes in the internal my_crypt.cc
encryption functions and in the encryption service.
There are wrappers to provide the old all-at-once encryption
functionality. But binlog events are often written piecewise,
they'll need the new api.
