New functions

    ERR_peek_last_error
    ERR_peek_last_error_line
    ERR_peek_last_error_line_data
(supersedes ERR_peek_top_error).

Rename OPENSSL_NO_OLD_DES_SUPPORT into OPENSSL_DISABLE_OLD_DES_SUPPORT
because OPENSSL_NO_... indicates disabled algorithms (according to
mkdef.pl).