Finally got back onto this project again for a while ...
You said that I should "... First, you need to remove the current openssl include headers."
However, I am a bit lost as to know where to locate them, in order to remove them. I guess it may be different on different systems, but if you're able to make some suggestions then that would be very useful to me.
Meantime, I have now downloaded both the libssh2 and openssl tarballs and extracted. I tried doing the libssh2 stuff you suggested, before having done anything else, and it errored with: "checking for OpenSSL... configure: error: Cannot find OpenSSL's <evp.h> or <hmac.h>"
So, I figured I needed to do the openssl stuff first. But, before doing that I wanted to make sure that I had removed the files you suggested ... and that's where I am right now.
Any assistance mightily appreciated. I think this might take me a while to do, since I'm on a bit of a learning curve here, but hope you can be patient :-)