reserved identifier violation about openage

[mic-e]

Hm... from various other C projects I've looked at/worked on, I was under the impression that this is how header guards are done, but you're of course right in that we should follow the standard. Standards are a great thing. I suggest we change the guards to CALLBACKS_H and ENGINE_TERRAIN_H as suggested in your link.

[mdparker]

Since the project is using C++ 11, there's no reason not to simply use "#pragma once" at the top of each header. All modern C++ compilers support, AFAIK.

[mic-e]

We've been considerating that... there are benefits, especially that classical guards are very prone to accidential name clashes or typos.
It's obviously useful, so I researched why it wasn't put into the standard. The answer seems to be that header files might be copy/pasted or reached over multiple paths through symlinks, confusing the compiler as to whether to include them with #pragma once.
I'm rather undecided right now... obviously the C++ standards commitee knows what they're doing*, so if they decide against #pragma once, maybe we should just accept that. Ideally, there would be something like #pragma once ENGINE_TERRAIN_H.

*disclaimer: actually they don't

P.S.: obligatory stackoverflow link

[mic-e]

Fixed by pull request #18