Preliminary Haiku support

[extrowerk]

With these patches it builds and works on Haiku (tested only on 64 bit with GCC7):

[extrowerk]

[AJenbo]

Nice Icon, but would it be possible to put it in a folder so that the name and intend is clear? Probably not many are familiar with .rdef.in files and as we start to support more platforms this could clutter the root.

[extrowerk]

Yeah, we can do that.
What do you think about a “platform/$osname” structure?
Or “resources/$osname”?

[AJenbo]

I was thinking resources/$osname

[AJenbo]

It looks like stormlib solved the same issue for FreeBSD by settings this in CMake:
https://github.com/ladislav-zezula/StormLib/blob/master/CMakeLists.txt#L303

I think we should go for the same solution here instead of modifying the stormlib source localy.

[AJenbo]

O_LARGEFILE should be disabled in StormPort.h
https://github.com/ladislav-zezula/StormLib/blob/4ad0bff21da0163917e1552960e6a43679586b89/src/StormPort.h#L202

It looks like this is also the place to define *64 functions, not sure why they ended up putting it in CMake for FreeBSD :/

[AJenbo]

Nice work upstreaming the storm changes. Should the aiso changes also be upstreamed?

[extrowerk]

@AJenbo : i tried to upstream the asio patches, but i had to see it is already done and merged. The devilution in-tree version is just too old.

[AJenbo]

Good to know

Again thanks for the PR