diff --git a/stepmania/src/CourseLoaderCRS.cpp b/stepmania/src/CourseLoaderCRS.cpp
index f76be33df1..653543a559 100644
--- a/stepmania/src/CourseLoaderCRS.cpp
+++ b/stepmania/src/CourseLoaderCRS.cpp
@@ -13,6 +13,7 @@
 #include "RageFileManager.h"
 #include "CourseWriterCRS.h"
 #include "RageUtil.h"
+#include <float.h>
 
 const int MAX_EDIT_COURSE_SIZE_BYTES	= 30*1024;	// 30KB
 
@@ -63,7 +64,7 @@ bool CourseLoaderCRS::LoadFromMsd( const RString &sPath, const MsdFile &msd, Cou
 		{
 			fGainSeconds = StringToFloat( sParams[1] );
 			
-			if( !isfinite(fGainSeconds) )
+			if( !finite(fGainSeconds) )
 				fGainSeconds = 0.0f;
 		}
 		else if( 0 == stricmp(sValueName, "METER") )
diff --git a/stepmania/src/PlayerOptions.cpp b/stepmania/src/PlayerOptions.cpp
index 663eab4391..7e96d1404a 100644
--- a/stepmania/src/PlayerOptions.cpp
+++ b/stepmania/src/PlayerOptions.cpp
@@ -12,6 +12,7 @@
 #include "Style.h"
 #include "CommonMetrics.h"
 #include "arch/Dialog/Dialog.h"
+#include <float.h>
 
 #define ONE( arr ) { for( unsigned Z = 0; Z < ARRAYSIZE(arr); ++Z ) arr[Z]=1.0f; }
 
@@ -257,7 +258,7 @@ void PlayerOptions::FromString( const RString &sOptions, bool bWarnOnInvalid )
 			else if( *s[0]=='*' )
 			{
 				sscanf( *s, "*%f", &speed );
-				if( !isfinite(speed) )
+				if( !finite(speed) )
 					speed = 1.0f;
 			}
 		}
@@ -279,7 +280,7 @@ void PlayerOptions::FromString( const RString &sOptions, bool bWarnOnInvalid )
 		}
 		else if( sscanf( sBit, "c%f", &level ) == 1 )
 		{
-			if( !isfinite(level) || level <= 0.0f )
+			if( !finite(level) || level <= 0.0f )
 				level = 200.0f; // Just pick some value.
 			SET_FLOAT( fScrollBPM )
 			SET_FLOAT( fTimeSpacing )
diff --git a/stepmania/src/RageUtil.cpp b/stepmania/src/RageUtil.cpp
index de484a0bed..7c92d845d2 100644
--- a/stepmania/src/RageUtil.cpp
+++ b/stepmania/src/RageUtil.cpp
@@ -6,6 +6,7 @@
 #include "Foreach.h"
 #include "LocalizedString.h"
 #include "LuaFunctions.h"
+#include <float.h>
 
 #include <numeric>
 #include <ctime>
@@ -1476,7 +1477,7 @@ float StringToFloat( const RString &sString )
 {
 	float ret = strtof( sString, NULL );
 	
-	if( !isfinite(ret) )
+	if( !finite(ret) )
 		ret = 0.0f;
 	return ret;
 }
@@ -1905,7 +1906,7 @@ bool FromString( const RString &sValue, float &out )
 {
 	const char *endptr = sValue.data() + sValue.size();
 	out = strtof( sValue, (char **) &endptr );
-	return endptr != sValue.data() && isfinite( out );
+	return endptr != sValue.data() && finite( out );
 }
 
 bool FromString( const RString &sValue, bool &out )