Use <cmath> M_PI instead of own "pi" constant

This solves a conflict with a definition with the same name within Apple SDK
headers (thanks, Mortimer)

src/C4Include.h

@@ -24,6 +24,11 @@
 #ifndef INC_C4Include
 #define INC_C4Include
 
+#ifdef _MSC_VER
+// Get non-standard <cmath> constants (M_PI etc.)
+#	define _USE_MATH_DEFINES
+#endif
+
 #include "PlatformAbstraction.h"
 #include "Standard.h"
 #include "C4Prototypes.h"
@@ -54,6 +59,7 @@
 #include <cctype>
 #include <cerrno>
 #include <climits>
+
 #include <cmath>
 #include <cstdarg>
 #include <cstddef>

src/game/landscape/C4Map.cpp

@@ -86,7 +86,7 @@ void C4MapCreator::Create(CSurface8 *sfcMap,
                           C4SLandscape &rLScape, C4TextureMap &rTexMap,
                           bool fLayers, int32_t iPlayerNum)
 {
-	double fullperiod= 20.0 * pi;
+	double fullperiod= 20.0 * M_PI;
 	BYTE ccol;
 	int32_t cx,cy;
 
@@ -128,7 +128,7 @@ void C4MapCreator::Create(CSurface8 *sfcMap,
 
 		cy_natural=rnd_cy*natural/100.0;
 		cy_curve=sin(fullperiod*period/100.0*(float)cx/(float)MapWdt
-		             +2.0*pi*phase/100.0) * amplitude/100.0;
+		             +2.0*M_PI*phase/100.0) * amplitude/100.0;
 
 		cy=level0+BoundBy((int32_t)((float)maxrange*(cy_curve+cy_natural)),
 		                  -maxrange,+maxrange);

src/game/script/C4Effect.cpp

@@ -698,8 +698,8 @@ int32_t FnFxFireTimer(C4AulContext *ctx, C4Object *pObj, int32_t iNumber, int32_
 	float fRot[4] = { 1.0f, 0.0f, 0.0f, 1.0f };
 	if (pObj->r && pObj->Def->Rotateable)
 	{
-		fRot[0] = (float) cosf((float) (pObj->r * pi/180.0));
-		fRot[1] = (float) -sinf((float) (pObj->r * pi/180.0));
+		fRot[0] = (float) cosf((float) (pObj->r * M_PI/180.0));
+		fRot[1] = (float) -sinf((float) (pObj->r * M_PI/180.0));
 		fRot[2] = -fRot[1];
 		fRot[3] = fRot[0];
 		// rotated objects usually better burn from the center

src/game/script/C4Script.cpp

@@ -2977,7 +2977,7 @@ static long FnAngle(C4AulContext *cthr, long iX1, long iY1, long iX2, long iY2,
 		else return 270 * iPrec;
 	}
 
-	iAngle = static_cast<long>(180.0 * iPrec * atan2(static_cast<double>(Abs(dy)), static_cast<double>(Abs(dx))) / pi);
+	iAngle = static_cast<long>(180.0 * iPrec * atan2(static_cast<double>(Abs(dy)), static_cast<double>(Abs(dx))) / M_PI);
 
 	if (iX2>iX1 )
 	{
@@ -3000,7 +3000,7 @@ static long FnArcSin(C4AulContext *cthr, long iVal, long iRadius)
 	if (iVal > iRadius) return 0;
 	// calc arcsin
 	double f1 = iVal;
-	f1 = asin(f1/iRadius)*180.0/pi;
+	f1 = asin(f1/iRadius)*180.0/M_PI;
 	// return rounded angle
 	return (long) floor(f1+0.5);
 }
@@ -3012,7 +3012,7 @@ static long FnArcCos(C4AulContext *cthr, long iVal, long iRadius)
 	if (iVal > iRadius) return 0;
 	// calc arccos
 	double f1 = iVal;
-	f1 = acos(f1/iRadius)*180.0/pi;
+	f1 = acos(f1/iRadius)*180.0/M_PI;
 	// return rounded angle
 	return (long) floor(f1+0.5);
 }

src/lib/Standard.cpp

@@ -24,7 +24,6 @@
 #include "C4Include.h"
 #include <StdSync.h>
 
-#include <math.h>
 #include <sys/timeb.h>
 
 //------------------------------------- Basics ----------------------------------------
@@ -42,7 +41,7 @@ int32_t Distance(int32_t iX1, int32_t iY1, int32_t iX2, int32_t iY2)
 
 int Angle(int iX1, int iY1, int iX2, int iY2)
 {
-	int iAngle = (int) ( 180.0 * atan2( float(Abs(iY1-iY2)), float(Abs(iX1-iX2)) ) / pi );
+	int iAngle = (int) ( 180.0 * atan2( float(Abs(iY1-iY2)), float(Abs(iX1-iX2)) ) / M_PI );
 	if (iX2>iX1 )
 		{ if (iY2<iY1) iAngle = 90-iAngle; else iAngle = 90+iAngle; }
 	else

src/lib/Standard.h

@@ -40,8 +40,6 @@ template <class T> inline int Sign(T val) { return val < 0 ? -1 : val > 0 ? 1 :
 template <class T> inline void Swap(T &v1, T &v2) { T t = v1; v1 = v2; v2 = t; }
 template <class T> inline void Toggle(T &v) { v = !v; }
 
-const double pi = 3.14159265358979323846;
-
 inline int DWordAligned(int val)
 {
 	if (val%4) { val>>=2; val<<=2; val+=4; }

src/platform/StdDDraw2.cpp

@@ -33,7 +33,6 @@
 #include "StdMesh.h"
 
 #include <stdio.h>
-#include <math.h>
 #include <limits.h>
 
 // Global access pointer
@@ -819,7 +818,7 @@ bool CStdDDraw::BlitRotate(SURFACE sfcSource, int fx, int fy, int fwdt, int fhgt
 
 	default:
 		// Calculate rotation matrix
-		dang=pi*iAngle/18000.0;
+		dang=M_PI*iAngle/18000.0;
 		mtx[0]=cos(dang); mtx[1]=-sin(dang);
 		mtx[2]=sin(dang); mtx[3]= cos(dang);
 		// Blit source rect

src/platform/StdJoystick.cpp

@@ -33,7 +33,6 @@ static uint32_t dwStdGamepadMinY = 0;
 
 #include <windows.h>
 #include <windowsx.h>
-#include <math.h>
 
 uint32_t POV2Position(DWORD dwPOV, bool fVertical)
 {
@@ -44,7 +43,7 @@ uint32_t POV2Position(DWORD dwPOV, bool fVertical)
 		dAxis = 0.0;
 	// Angle: convert to linear value -100 to +100
 	else
-		dAxis = (fVertical ? -cos((dwPOV/100) * pi / 180.0) : sin((dwPOV/100) * pi / 180.0)) * 100.0;
+		dAxis = (fVertical ? -cos((dwPOV/100) * M_PI / 180.0) : sin((dwPOV/100) * M_PI / 180.0)) * 100.0;
 	// Gamepad configuration wants unsigned and gets 0 to 200
 	return (uint32_t) (dAxis + 100.0);
 }