Various Linux fixes

Закрыто xottab-duty запросил слияние github/fork/a1batross/linux_fixes в xd_dev

Created by: a1batross

Just checking Linux port state. :)

  • xrCore, xrCDB, OPCODE, ode now builds.
  • Tried to fix xrSound, but SoundRender_Stream still uses DirectSound. Needs to be ported(OpenAL?).
  • Some fixes in EAX SDK headers, but it's useless due to EAX does not works on Linux itself. Just make compilable.