tlsdate fails to build with openssl-1.1 (new API)

[Polynomial-C]

x86_64-pc-linux-gnu-gcc -DHAVE_CONFIG_H -I.     -march=native -mtune=native -O2 -pipe  -Wall -fno-strict-aliasing -c -o src/src_tlsdate_helper-tlsdate-helper.o `test -f 'src/tlsdate-helper.c' || echo './'`src/tlsdate-helper.c
src/tlsdate-helper.c: In function ‘openssl_time_callback’:
src/tlsdate-helper.c:377:11: error: dereferencing pointer to incomplete type ‘SSL {aka const struct ssl_st}’
       (ssl->state == SSL3_ST_CR_SRVR_HELLO_A || ssl->state == SSL3_ST_CR_SRVR_H
           ^
src/tlsdate-helper.c:377:22: error: ‘SSL3_ST_CR_SRVR_HELLO_A’ undeclared (first use in this function)
       (ssl->state == SSL3_ST_CR_SRVR_HELLO_A || ssl->state == SSL3_ST_CR_SRVR_H
                      ^
src/tlsdate-helper.c:377:22: note: each undeclared identifier is reported only once for each function it appears in
src/tlsdate-helper.c:377:63: error: ‘SSL3_ST_CR_SRVR_HELLO_B’ undeclared (first use in this function)
       (ssl->state == SSL3_ST_CR_SRVR_HELLO_A || ssl->state == SSL3_ST_CR_SRVR_H
                                                               ^
src/tlsdate-helper.c: In function ‘get_certificate_keybits’:
src/tlsdate-helper.c:414:21: error: dereferencing pointer to incomplete type ‘EVP_PKEY {aka struct evp_pkey_st}’
   switch (public_key->type)
                     ^
src/tlsdate-helper.c:418:18: warning: implicit declaration of function ‘BN_num_bits’ [-Wimplicit-function-declaration]
       key_bits = BN_num_bits(public_key->pkey.rsa->n);
                  ^
src/tlsdate-helper.c: In function ‘check_san’:
src/tlsdate-helper.c:698:18: error: dereferencing pointer to incomplete type ‘X509_EXTENSION {aka struct X509_extension_st}’
         tmp = ext->value->data;
                  ^
src/tlsdate-helper.c: In function ‘run_ssl’:
src/tlsdate-helper.c:1128:3: warning: implicit declaration of function ‘SSL_load_error_strings’ [-Wimplicit-function-declaration]
   SSL_load_error_strings();
   ^
src/tlsdate-helper.c:1129:3: warning: implicit declaration of function ‘SSL_library_init’ [-Wimplicit-function-declaration]
   SSL_library_init();
   ^
src/tlsdate-helper.c:1147:23: warning: implicit declaration of function ‘TLSv1_client_method’ [-Wimplicit-function-declaration]
     ctx = SSL_CTX_new(TLSv1_client_method());
                       ^
src/tlsdate-helper.c:1147:23: warning: passing argument 1 of ‘SSL_CTX_new’ makes pointer from integer without a cast [-Wint-conversion]
In file included from ./src/tlsdate-helper.h:38:0,
                 from src/tlsdate-helper.c:78:
/usr/include/openssl/ssl.h:1302:17: note: expected ‘const SSL_METHOD * {aka const struct ssl_method_st *}’ but argument is of type ‘int’
 __owur SSL_CTX *SSL_CTX_new(const SSL_METHOD *meth);
                 ^
src/tlsdate-helper.c:1211:27: error: dereferencing pointer to incomplete type ‘SSL {aka struct ssl_st}’
   memcpy(&result_time, ssl->s3->server_random, sizeof (uint32_t));
                           ^
make[1]: *** [Makefile:1972: src/src_tlsdate_helper-tlsdate-helper.o] Error 1
make[1]: Leaving directory '/var/tmp/portage/net-misc/tlsdate-0.0.13/work/tlsdate-0.0.13'
make: *** [Makefile:1366: all] Error 2

See also openssl-1.1 API changes

[Polynomial-C]

Please also note that openssl-1.1 can be compiled with three different compatibility levels:

--api=0.9.8, --api=1.0.0 and --api=1.1.0.

The important information here is that with --api=1.1.0 all interfaces seen as deprecated by openssl developers won't be available anymore. So please carefully check your code for usage of deprecated interfaces.