Make OpenSSL link to "libcrypto" on Windows

[JD557]

Windows binary distributions of OpenSSL use libcrypto.lib instead of crypto.lib (this pattern seems quite common for reasons that I do not understand).

This PR updates the code to use the correct linking flag depending on the OS.

Tested by checking that the unit tests ran both on Mac OS and on Windows 11 (Using Shining Light's OpenSSL binary distribution)