Macro to handle legacy OpenSSL SSLeay_add_all_algorithms()

[Germano0]

Hi, I am one of the Fedora Owncloud-Client maintainers.
Fedora Rawhide (26) ships OpenSSL 1.1.0 that no longer permits to call the old SSLeay_add_all_algorithms() that has been replaced with OpenSSL_add_all_algorithms() since OpenSSL version 0.9.5. So we started getting build failures
I solved by adding a macro that calls

• SSLeay_add_all_algorithms() if the system uses OpenSSL <= 0.9.4
• OpenSSL_add_all_algorithms() if the system uses OpenSSL > 0.9.4
  The hexadecimal code for OpenSSL 0.9.4 version has been taken from [here] (https://github.com/openssl/openssl/blob/6f0ac0e2f27d9240516edb9a23b7863e7ad02898/include/openssl/opensslv.h#L29)

Best regards
Germano Massullo

[CLAassistant]

All committers have signed the CLA.

[mention-bot]

@Germano0, thanks for your PR! By analyzing the history of the files in this pull request, we identified @nocteau and @danimo to be potential reviewers.

[guruz]

Thanks for the PR.
After merging https://github.com/owncloud/client/pull/5289/files we would not need your PR anymore, sorry :-)

I'll keep it here still since we'd need to have it if we ever decide to do a 2.2.5 then we could cherry-pick your PR there.

[ogoffart]

@guruz: maybe the patch that gets rid of p12topem.cpp could be merged now already?

[guruz]

2.3.0 is released, thanks anyway :)