openssl 1.1 vs. 3.0 for vibe.d:tls on Ubuntu 22.04

[Guillaume Lathoud]

Hello, some context first:

I recently updated a server to Ubuntu 22.04 which appears to have 
only openssl 3.0.2 installed. Dub could compile my project, but 
could not link it anymore, as the D code seemed to be expecting 
openssl 1.1 whereas only 3.0.2 was installed. That type of errors:
```
/usr/bin/ld: 
...../vibe-d-0.9.6/vibe-d/tls/vibe/stream/openssl.d:370: 
undefined reference to `SSL_get_peer_certificate'
/usr/bin/ld: 
...../vibe-d-0.9.6/vibe-d/tls/vibe/stream/openssl.d:1485: 
undefined reference to `ERR_put_error'
collect2: error: ld returned 1 exit status
```
I tried various things, including all possible `subConfiguration` 
values for `vibe-d:tls`, and ended up:

(1) selecting `"vibe-d:tls": "openssl-1.1"`

(2) compiling openssl-1.1 from source following  
https://askubuntu.com/a/1458747

(3) symlinking the resulting files `libssl.a` and `libcrypto.a` 
into LDC's `lib` directory, since libs under that dir seem to 
have precedence over the system libs, as visible in the 
`/usr/bin/cc` call triggered by DUB.

Then  the project compiled again.

.

Now to the actual question:

I am a bit confused since the source code of `vibe-d:tls` seem to 
support openssl-3.0, as visible e.g. in [1] but then in the 
config [2] I don't see anything like `"openssl-3.0"`. Maybe I 
missed something obvious!

[1] 
https://github.com/vibe-d/vibe.d/blob/master/tls/vibe/stream/openssl.d#L198
[2] https://github.com/vibe-d/vibe.d/blob/master/tls/dub.sdl

Could anyone please shed some light on a cleaner solution to get 
`vibe.d:tls` running on Ubuntu 22.04, esp. to get it running with 
openssl-3.0+?

Thanks in advance,
Guillaume

.

For info, the project has the following `dub.json` config:
```
...
        "dependencies": {
                 "dub": "~>1.33.1",
                 "openssl": "~>3.3",
                 "vibe-d": "~>0.9.6",
                 "vibe-d:tls": "~>0.9.6"
         },                                                        
                                                                   
                                                          ...
         "libs": [
                 "curl"
         ],
...
        "subConfigurations": {
             "vibe-d:tls": "openssl-1.1"
         },
         "versions": [
                 "VibeDefaultMain"
         ]
...
```