avoid problem with clang and math func in constexpr, clang is prob. right

Processes/Sibyll/Interaction.h

@@ -125,10 +125,13 @@ namespace corsika::process::sibyll {
     //
     // number of steps in energy for cross section table (sibyll internal value is 61)
     static constexpr int fNenBins = 61;
-    static constexpr double fLog10MinEnergyCoM =
-        log10(fMinEnergyCoM / 1e9 / corsika::units::si::electronvolt);
-    static constexpr double fLog10MaxEnergyCoM =
-        log10(fMaxEnergyCoM / 1e9 / corsika::units::si::electronvolt);
+    // hard code log10 of limits given above
+    static constexpr double fLog10MinEnergyCoM = 1.;
+    // clang does not like:        log10(fMinEnergyCoM / 1e9 /
+    // corsika::units::si::electronvolt);
+    static constexpr double fLog10MaxEnergyCoM = 7.;
+    // clang does not like:       log10(fMaxEnergyCoM / 1e9 /
+    // corsika::units::si::electronvolt);
     static constexpr double fDeltaLog10EnergyCoM =
         (fLog10MaxEnergyCoM - fLog10MinEnergyCoM) / double(fNenBins);