[openssl-dev] libcrypto.pc needs to list libpthread as a dependency

[Roumen Petrov]

Howard Chu via openssl-dev wrote:
> In OpenSSL 1.1 on Linux (at least) libcrypto now has a dependency on 
> libpthread but this is not reflected in the pkgconfig file. As a 
> result, tools like CMake fail to detect libcrypto properly when 
> linking against the static library. libpthread should be added to the 
> Libs.private line of the pkgconfig file.
>
> For example: 
> https://github.com/monero-project/monero/issues/2402#issuecomment-327514216

Problem is that OpenSSL does not add it directly.
Build process does not know libraries added by compiler flags like -pthread.

Does not look like OpenSSL issue.

Regards,
Roumen