Description

The changes here ensure that:

1. OPENSSL_API_COMPAT is always defined before including any OpenSSL header
2. It is never redefined, as we #undef it before defining it

@Mergifyio backport 3.1.x 3.0.x

Contributor Checklist

• Commit messages follow the project guidelines.

• The code follows the style guidelines of this project.

• NO: Tests that thoroughly check the new feature have been added/Regression tests checking the bug and its fix have been added; the added tests pass locally

  • With our current CI infrastructure I found no way of reproducing the redefinition warning, but I locally checked that an equivalent of this built successfully

• N/A: Any new/modified methods have been properly documented using Doxygen.

• N/A: Any new configuration API has an equivalent XML API (with the corresponding XSD extension)

• Changes are backport compatible: they do NOT break ABI nor change library core behavior.

• Changes are API compatible.

• N/A: New feature has been added to the versions.md file (if applicable).

• N/A: New feature has been documented/Current behavior is correctly described in the documentation.

• Applicable backports have been included in the description.

Reviewer Checklist

• The PR has a milestone assigned.
• The title and description correctly express the PR's purpose.
• Check contributor checklist is correct.
• If this is a critical bug fix, backports to the critical-only supported branches have been requested.
• Check CI results: changes do not issue any warning.
• Check CI results: failing tests are unrelated with the changes.