Fix warnings in casacore's constants

src/h5parm/jonesparameters.cc

@@ -7,6 +7,7 @@
 #include <casacore/casa/BasicSL/Constants.h>
 
 #include <cassert>
+#include <cmath>
 #include <utility>
 
 #include <aocommon/matrix2x2.h>
@@ -170,13 +171,13 @@ void JonesParameters::MakeComplex(
         break;
       case GainType::kClock:
         parms_(0, ant, tf) =
-            StablePolar(1., parm_values[0][ant][tf] * freq * casacore::C::_2pi);
+            StablePolar(1., parm_values[0][ant][tf] * freq * 2.0 * M_PI);
         if (parm_values.size() == 1) {  // No Clock:0, only Clock:
-          parms_(1, ant, tf) = StablePolar(
-              1., parm_values[0][ant][tf] * freq * casacore::C::_2pi);
+          parms_(1, ant, tf) =
+              StablePolar(1.0, parm_values[0][ant][tf] * freq * 2.0 * M_PI);
         } else {  // Clock:0 and Clock:1
-          parms_(1, ant, tf) = StablePolar(
-              1., parm_values[1][ant][tf] * freq * casacore::C::_2pi);
+          parms_(1, ant, tf) =
+              StablePolar(1.0, parm_values[1][ant][tf] * freq * 2.0 * M_PI);
         }
         break;
       case GainType::kRotationAngle: {