Marked the crypto backend registration APIs as deprecated

This is to warn for a future conversion of these APIs to a no-op.

Checklist

• Commits have Signed-off-by: with name/author being identical to the commit author
• Code modified for feature

Reviewer's checklist:

• Any issues marked for closing are addressed
• There is a test suite reasonably covering new functionality or modifications
• Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTION.md
• This feature/change has adequate documentation added
• No obvious mistakes in the code

changed milestone to %Release of GnuTLS 3.6.9

added need review label

Is this of any concert for internal GnuTLS code (like cryptodev or now-closed afalg MR). Also should we also deprecate gnutls_single_FOO_register() family?

Internally we can keep the registration API which we have full control of (e.g., adding, removing functionality). This deprecation is not affecting any internally used API. The intent is to remove any public API so that when we need to add hmac_copy for example, we do not have to account for applications that may have overriden the internal implementation with one that doesn't implement copy. The gnutls_single_FOO_register() is not exported (as far as I see), thus we should be fine with it.

marked the checklist item Function naming, parameters, return values, types, etc., are consistent and according to CONTRIBUTION.md as completed

marked the checklist item Any issues marked for closing are addressed as completed

marked the checklist item This feature/change has adequate documentation added as completed

marked the checklist item No obvious mistakes in the code as completed

approved this merge request

marked the checklist item There is a test suite reasonably covering new functionality or modifications as completed

resolved all discussions

added 1 commit

• 7736f574 - Marked the crypto backend registration APIs as deprecated

Compare with previous version

enabled an automatic merge when the pipeline for 7736f574 succeeds

merged

mentioned in commit 4292c1ae

assigned to @nmav