OpenSSL 3.0.0 deprecates ENGINE APIs

[tatsuhiro-t]

https://www.openssl.org/docs/man3.0/man7/migration_guide.html

It looks like OpenSSL 3.0.0 deprecates ENGINE related APIs and bunch of low-level getters and setters.
There are lots of deprecation warnings when compiled with OpenSSL 3.0.0.

[krowbar]

A fix for me using libressl (pretty sure it's the same issue) is to use the OPENSSL_NO_ENGINE def (from /usr/local/include/openssl/opensslfeatures.h) in neverbleed.c.

--- deps/neverbleed/neverbleed.c.orig   2023-12-11 18:48:55 UTC
+++ deps/neverbleed/neverbleed.c
@@ -2220,6 +2220,7 @@ int neverbleed_init(neverbleed_t *nb, char *errbuf)
         EC_KEY_METHOD_set_sign(ecdsa_method, ecdsa_sign_proxy, NULL, NULL);
 #endif

+#if !defined(OPENSSL_NO_ENGINE)
         if ((nb->engine = ENGINE_new()) == NULL || !ENGINE_set_id(nb->engine, "neverbleed") ||
             !ENGINE_set_name(nb->engine, "privilege separation software engine") || !ENGINE_set_RSA(nb->engine, rsa_method)
 #ifdef NEVERBLEED_ECDSA
@@ -2230,6 +2231,7 @@ int neverbleed_init(neverbleed_t *nb, char *errbuf)
             goto Fail;
         }
         ENGINE_add(nb->engine);
+#endif
     }
 #endif

Going by the name, I would think it is not libressl specific.