Lots of fixes for the Linux build:

- renamed sysdep/unix/ functions where necessary
- more int -> LibError conversions in the sysdep/unix/ part
- added some explicit #include statements where necessary
- moved enum LibError/ErrorReaction declarations
  (gcc doesn't support forward enum declarations)

This was SVN commit r3267.

source/graphics/UnitManager.cpp

@@ -8,6 +8,8 @@
 
 #include "precompiled.h"
 
+#include <float.h>
+
 #include "lib/res/res.h"
 #include "Model.h"
 #include "UnitManager.h"