Linkage of static library from `/usr/lib64` ignored with `-L` flag warning

[drahnr]

Using fedora 27, openssl-static provides /usr/lib64/libssl.so and /usr/lib64/libcrypto.so.

The below commit prevents this from linking properly.

9a57960

Expectation: If I set OPENSSL_STATIC I'd either expect the whole thing to fail, print a very descriptive warning with a hint on how to fix this.
What happens actually: a) Missing -L flag warning, b) links dynamically (which I explicitly want to prevent (need to share this from Ubuntu 16.04 over Arch to Fedora Rawhide)

I also opend a topic: https://users.rust-lang.org/t/how-to-link-openssl-statically/14912/2
Also filed: sfackler/rust-openssl#825 (comment)
Possibly related: #37

[alexcrichton]

Thanks for the report!

Unfortunately I don't know a great way to solve this. This was added in place because you typically don't want to statically link system libraries (even with pkg-config --static), but instead you only want to link a library you just compiled or something like that. Threading that needle I think would be pretty difficult.

[drahnr]

I think there should be at least (another?) env var (SYSTEM_LIB_FORCE_STATIC_LINK) which can force this behaviour. I am not questioning the default behaviour.

Another issue: Dependent libs like -lz fail to link ( https://users.rust-lang.org/t/how-to-link-openssl-statically/14912/2 ), but that might be a separate issue.

[alexcrichton]

Perhaps? That may or may not work, it'd be good to test if it actually does. I've never had success statically linking from system-installed versions, I've personally found that you basically always need to compile your own version for various reasons.

[drahnr]

I understand that this might be the case, but it might also be not - right now the only thing that comes to my mind (i.e. for openssl) is the set of config options selected by the distribution. Maybe I am missing something obvious.