security/tor: Fix build with LibreSSL

[zirias]

Summary

LibreSSL doesn't support the ENGINE API and defines the
OPENSSL_NO_ENGINE feature flag, tor uses that feature flag, but misses
to include openssl/opensslconf.h which is necessary to pull in the
feature flags at least with LibreSSL, therefore add that include.

[yuri]

security/tor/files/patch-src_lib_crypt__ops_crypto__openssl__mgt.c

12 ↗

(On Diff #131065)

Doesn't this #endif statement break the original code structure?
The #else above it had some continuation, which is now differently conditioned.

[zirias]

security/tor/files/patch-src_lib_crypt__ops_crypto__openssl__mgt.c

12 ↗

(On Diff #131065)

It certainly does, thanks a lot for spotting this massive brainfart. I must have misread the #else as an #endif. I'll do some more testing with the fixed logic first, to make sure I really only disable logging of what LibreSSL currently doesn't provide, then update the review accordingly.

[zirias]

Having another look was very helpful, turned out the few ENGINE_* calls LibreSSL *does* provide are just stubs returning NULL. Even code disabling engines based on the OPENSSL_NO_ENGINE feature flag was already there, it just didn't work because opensslconf.h was not included, which is necessary at least with LibreSSL to get the feature flags. This might even be a fix for upstream now ...