Remove sign/verify and required_pkey_type fields of EVP_MD: these are a
legacy from when digests were linked to public key types. All signing is
now handled by the corresponding EVP_PKEY_METHOD.

Only allow supported digest types in RSA EVP_PKEY_METHOD: other algorithms
already block unsupported types.

Remove now obsolete EVP_dss1() and EVP_ecdsa().
Reviewed-by: NRichard Levitte <levitte@openssl.org>

Continuing from previous work standardise use of malloc in the engine code.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>

Problem was exposed in mingw64 build, or in other words on P64 platform.
Reviewed-by: NRich Salz <rsalz@openssl.org>

The ossltest engine wraps the built-in implementation of aes128-cbc.
Normally in an engine the cipher_data structure is automatically allocated
by the EVP layer. However this relies on the engine specifying up front
the size of that cipher_data structure. In the case of ossltest this value
isn't available at compile time. This change makes the ossltest engine
allocate its own cipher_data structure instead of leaving it to the EVP
layer.
Reviewed-by: NAndy Polyakov <appro@openssl.org>

Use a dynamic engine for ossltest engine so that we can build it without
subsequently deploying it during install. We do not want people accidentally
using this engine.
Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

This engine is for testing purposes only. It provides crippled crypto
implementations and therefore must not be used in any instance where
security is required.

This will be used by the forthcoming libssl test harness which will operate
as a man-in-the-middle proxy. The test harness will be able to modify
TLS packets and read their contents. By using this test engine packets are
not encrypted and MAC codes always verify.
Reviewed-by: NRichard Levitte <levitte@openssl.org>