Remove TMath dependencies from TTimestamp.cxx

Author: xvallspl

core/base/src/TTimeStamp.cxx

@@ -38,7 +38,6 @@ NOTE: the use of time_t (and its default implementation as a 32 int)
 */
 
 #include "TTimeStamp.h"
-#include "TMath.h"
 #include "TString.h"
 #include "TError.h"
 #include "Riostream.h"
@@ -191,12 +190,13 @@ Double_t TTimeStamp::AsGMST(Double_t UT1Offset) const
 
 Double_t TTimeStamp::AsGAST(Double_t UT1Offset) const
 {
+   Double_t Pi = 3.14159265358979323846;
    Double_t D = (AsJulianDate() + UT1Offset/86400000.0) - 2451545.0;
-   Double_t epsilon = (23.4393 - 0.0000004*D)*TMath::Pi()/180.0;
-   Double_t L = (280.47 + 0.98565*D)*TMath::Pi()/180.0;
-   Double_t Omega = (125.04 - 0.052954*D)*TMath::Pi()/180.0;
-   Double_t Deltapsi = -0.000319*TMath::Sin(Omega) - 0.000024*TMath::Sin(2.0*L);
-   Double_t eqeq = Deltapsi*TMath::Cos(epsilon);
+   Double_t epsilon = (23.4393 - 0.0000004 * D) * Pi / 180.0;
+   Double_t L = (280.47 + 0.98565 * D) * Pi / 180.0;
+   Double_t Omega = (125.04 - 0.052954 * D) * Pi / 180.0;
+   Double_t Deltapsi = -0.000319 * std::sin(Omega) - 0.000024 * std::sin(2.0 * L);
+   Double_t eqeq = Deltapsi * std::cos(epsilon);
    Double_t rval = fmod(AsGMST(UT1Offset) + eqeq, 24.0);
    return rval < 0 ? rval + 24.0 : rval;
 }