ATS 7.0.0 build fails with OpenSSL 1.1.0c

[Jean Baptiste Favre <we...@jbfavre.org>]

Hello,
I'm preparing Debian package for ATS 7.0.0.
Build currently fails with following error:

SSLInternal.cc: In function ‘void SSL_set_rbio(SSL*, BIO*)’:
SSLInternal.cc:40:10: error: invalid use of incomplete type ‘SSL {aka
struct ssl_st}’
   if (ssl->rbio != NULL) {
          ^~
In file included from /usr/include/openssl/crypto.h:31:0,
                 from /usr/include/openssl/comp.h:16,
                 from /usr/include/openssl/ssl.h:47,
                 from SSLInternal.cc:33:
/usr/include/openssl/ossl_typ.h:144:16: note: forward declaration of
‘SSL {aka struct ssl_st}’
 typedef struct ssl_st SSL;
                ^~~~~~
SSLInternal.cc:41:17: error: invalid use of incomplete type ‘SSL {aka
struct ssl_st}’
     BIO_free(ssl->rbio);
                 ^~
In file included from /usr/include/openssl/crypto.h:31:0,
                 from /usr/include/openssl/comp.h:16,
                 from /usr/include/openssl/ssl.h:47,
                 from SSLInternal.cc:33:
/usr/include/openssl/ossl_typ.h:144:16: note: forward declaration of
‘SSL {aka struct ssl_st}’
 typedef struct ssl_st SSL;
                ^~~~~~
SSLInternal.cc:43:6: error: invalid use of incomplete type ‘SSL {aka
struct ssl_st}’
   ssl->rbio = rbio;
      ^~
In file included from /usr/include/openssl/crypto.h:31:0,
                 from /usr/include/openssl/comp.h:16,
                 from /usr/include/openssl/ssl.h:47,
                 from SSLInternal.cc:33:
/usr/include/openssl/ossl_typ.h:144:16: note: forward declaration of
‘SSL {aka struct ssl_st}’
 typedef struct ssl_st SSL;
                ^~~~~~

The full configure log can be found here:
https://gist.github.com/jbfavre/00f63362b435d8ffc682d42d29b671f2

According to https://wiki.openssl.org/index.php/1.1_API_Changes :
"setting SSL->rbio without setting SSL->wbio. New function introduction
in 1.1.0 to handle this: SSL_set_rbio()".
Problem is, rbio doesn't seems to be nicely detected at configure stage:

> checking for SSL_set_rbio... no
> checking whether to enable set rbio... no

Binding ATS to OpenSSL 1.0 still works.

Regards,
Jean Baptiste Favre