Configuration:

  Detected OS:           openbsd6.3
  Install path:          /usr/local
  Compilation arch:      openbsd

  Compiler:              gcc
  Compiler flags:         -g -O2

  Library-specific flags:
    TLS:                   -I/usr/include
    iconv:                 -I/usr/local/include

  Enable server:         no

  Enable proxy:          no

  Enable agent:          yes
  Agent details:
    TLS:                   OpenSSL
    Linker flags:           -L/usr/lib    -L/usr/local/lib
    Libraries:              -lssl -lcrypto   -lkvm -lm   -liconv

  Enable Java gateway:   no

  LDAP support:          no
  IPv6 support:          no

tls.c:226: error: 'PSK_MAX_IDENTITY_LEN' undeclared here (not in a function)
*** Error 1 in src/libs/zbxcrypto (Makefile:457 'libzbxcrypto_a-tls.o': gcc -DHAVE_CONFIG_H -I. -I../../../include    -I/usr/include -g -O2 ...)
*** Error 1 in src/libs (Makefile:494 'all-recursive')
*** Error 1 in src (Makefile:470 'all-recursive')
*** Error 1 in /home/zabbix/zabbix-3.0.25 (Makefile:483 'all-recursive')

tls.c:232:59: error: use of undeclared identifier 'PSK_MAX_IDENTITY_LEN'
ZBX_THREAD_LOCAL static char                    incoming_connection_psk_id[PSK_MAX_IDENTITY_LEN + 1];
                                                                           ^
tls.c:2645:3: warning: implicit declaration of function 'OPENSSL_cleanup' is invalid in C99 [-Wimplicit-function-declaration]
                OPENSSL_cleanup();
                ^
tls.c:3431:4: warning: implicit declaration of function 'SSL_CTX_set_psk_client_callback' is invalid in C99 [-Wimplicit-function-declaration]
                        SSL_CTX_set_psk_client_callback(ctx_psk, zbx_psk_client_cb);
                        ^
tls.c:3435:4: warning: implicit declaration of function 'SSL_CTX_set_psk_server_callback' is invalid in C99 [-Wimplicit-function-declaration]
                        SSL_CTX_set_psk_server_callback(ctx_psk, zbx_psk_server_cb);
                        ^
tls.c:3448:12: warning: implicit declaration of function 'SSL_CTX_set_ciphersuites' is invalid in C99 [-Wimplicit-function-declaration]
                if (1 != SSL_CTX_set_ciphersuites(ctx_psk, ZBX_CIPHERS_PSK_TLS13))
                         ^