This PR seems to solve the problem with empty password on macOS (OpenSSL 3.4.0).

However, on Ubuntu 24.10 (OpenSSL 3.3.1), the example prompts for the password with or without the code change.

Let's move this to 1.15.

Superseded by #5128, which provides a more complete fix that works on both macOS and Linux.

The issue with PR #4799 was that it only changed pPassword but kept pCB (callback) as NULL when password was empty. On Linux, when the callback is NULL, OpenSSL ignores pPassword entirely and still prompts stdin.

The fix in #5128 always provides the callback, which correctly handles empty passwords by returning 0 (no password), causing OpenSSL to throw a proper error.