Clean up math functions

- Remove checking for standard functions from the build system
- Prefix all invocations with std::
- Replace suffixed functions with unprefixed versions
- Include <cmath> in all files that use it and remove the global include

e.g. floorf(x) -> std::floor(x)

src/WheelNotifyIcon.cpp

@@ -7,6 +7,8 @@
 #include "RageTimer.h"
 #include "ThemeManager.h"
 
+#include <cmath>
+
 /* todo: replace this entire thing with a set of AutoActors and a Scroller.
  * In reality, everything except the Beginner/Training icon can be replicated
  * in Lua (in stock StepMania 4), so I'm not sure if we even need this... -aj
@@ -82,9 +84,9 @@ void WheelNotifyIcon::Update( float fDeltaTime )
 	if( m_vIconsToShow.size() > 0 )
 	{
 		/* We should probably end up parsing the vector and then dynamically
-		 * insert flag icons based on "priority". Easy to do, hopefully 
+		 * insert flag icons based on "priority". Easy to do, hopefully
 			- Midiman */
-		const float fSecondFraction = fmodf( RageTimer::GetTimeSinceStartFast(), 1 );
+		const float fSecondFraction = std::fmod( RageTimer::GetTimeSinceStartFast(), 1 );
 		const int index = (int)(fSecondFraction*m_vIconsToShow.size());
 		Sprite::SetState( m_vIconsToShow[index] );
 	}
@@ -95,7 +97,7 @@ void WheelNotifyIcon::Update( float fDeltaTime )
 /*
  * (c) 2001-2004 Chris Danford
  * All rights reserved.
- * 
+ *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
@@ -105,7 +107,7 @@ void WheelNotifyIcon::Update( float fDeltaTime )
  * copyright notice(s) and this permission notice appear in all copies of
  * the Software and that both the above copyright notice(s) and this
  * permission notice appear in supporting documentation.
- * 
+ *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF