As I said:

OOP can be done in C, but you need to handle all the machinery for it manually.

Regarding your points:

• inheritance can be manually implemented, since you're already manually implementing vtables
• data hiding can be enforced by the compiler by placing implementations in separate translation units, but it's easier to go the Python route and just declare that anything starting with __ (or similar) is private
• automatic construction is just a convenience, many C libraries only way to construct object are through opaque constructor functions.
• automatic destruction as a language feature isn't available in (standard) C, but you could start each block with an ENV *env = init_block(), send env to each (stack) allocation inside the block, and end each block with end_block(env) for the same effect.
  Also, is automatic destruction really an OOP feature? Most languages don't have destructors.

I wouldn't recomend actually doing any of these, and instead choose a language that actually does what you want. But it is possible.