Fixed VS compilation.

src/karts/controller/arena_ai.hpp

@@ -28,12 +28,6 @@
 #include "graphics/irr_driver.hpp"
 #endif
 
-#if defined(WIN32) && !defined(__CYGWIN__) && !defined(__MINGW32__)
-#define isnan _isnan
-#else
-#include <math.h>
-#endif
-
 class Vec3;
 
 namespace irr

src/karts/controller/battle_ai.cpp

@@ -33,12 +33,6 @@ using namespace irr;
 using namespace std;
 #endif
 
-#if defined(WIN32) && !defined(__CYGWIN__) && !defined(__MINGW32__)
-#define isnan _isnan
-#else
-#include <math.h>
-#endif
-
 BattleAI::BattleAI(AbstractKart *kart)
          : ArenaAI(kart)
 {

src/utils/vs.hpp

@@ -26,7 +26,6 @@
 #if defined(WIN32) && defined(_MSC_VER) && _MSC_VER < 1800
 #  include <math.h>
 
-#  define isnan _isnan
 #  define roundf(x) (floorf(x + 0.5f))
 #  define round(x)  (floorf(x + 0.5))
 #endif