Update for OpenSSL >= 1.1.0 #85

Needs #ifdef guards for OpenSSL < 1.1

Hi Tim, same applies here. Could you sign-off your commit with -s? Thanks.

Thanks Tim! 😄

No problem. It's great to be able to work on TDE again, even for a short time!

I added #ifdef to re-enable compatibility with OpenSSL < 1.1 and hope to LibreSSL as well. Tested successfully on Bullseye and Jessie.

In any case, as a separate task, it will be useful here to replace direct calls to SSL functions with KSSL proxy functions, so that we again avoid direct dependence on SSL libraries for tdelibs.

I looked into adding those KOpenSSLProxy functions, only to realize at build time that this would add a circular dependency between tdecore and tdeio. So we either don't use the proxy in tdecore (as it is now) or we need to move KOpenSSLProxy to tdecore.

What is your opinion?

Very good comment about KSSL and tdecore × tdeio! I didn't realize it before. I suggest merging this PR now and then finding a solution to remove the SSL hard linking as a separate issue.

I agree we can merge. Let me add a small code refactoring later tonight, then we can merge.

I added a small commit that refactors the code, getting rid of one #ifdef block and unifying the syntax of the other 3 #ifdef.

If no further comments or objections, we can merge.