OpenSSL
OpenSSL is a widely used, but occasionally problematic package.
Project website:Â https://www.openssl.org/Â
Since it's widely used, it generally comes with many systems and builds cleanly on most others, but it can be tricky to build correctly at times, is versioned improperly and inconsistently when it comes to shared libraries, and does not support debug builds on Windows.
The trickiest issue is that on platforms where OpenSSL is not native, you may run into multiple versions and find that different pieces of software used by or with Shibboleth are linked to different versions. This will NOT work, and you will get errors or crashes.
On platforms with a version included with the OS, it is strongly suggested that you stick with that version. If you're relying on mechanisms like the Mac ports project or one of Solaris' many open source initiatives, you will have to use a uniform set of software that is provided by those channels, including things like libcurl and Apache. So it's all or nothing, essentially, don't try and mix things.
Non-Windows
OpenSSL uses a front-end to the autoconf process that sometimes has trouble detecting the right platform and compiler, particularly on Solaris. It's critical to double-check the output of the initial step to make sure it picked the right settings.
A typical command to autodetect the platform might be:
./Configure threads shared
And for gcc:
./Configure solaris-sparcv9-gcc threads shared
Windows
See this topic