gcc8: error: expression '<throw-expression>' is not a constant expression

Index: al/state.cpp
--- al/state.cpp.orig
+++ al/state.cpp
@@ -140,8 +140,9 @@ constexpr auto ALenumFromDistanceModel(DistanceModel m
     case DistanceModel::LinearClamped: return AL_LINEAR_DISTANCE_CLAMPED;
     case DistanceModel::Exponent: return AL_EXPONENT_DISTANCE;
     case DistanceModel::ExponentClamped: return AL_EXPONENT_DISTANCE_CLAMPED;
+    default:
+        throw std::runtime_error{"Unexpected distance model "+std::to_string(static_cast<int>(model))};
     }
-    throw std::runtime_error{"Unexpected distance model "+std::to_string(static_cast<int>(model))};
 }
 
 enum PropertyValue : ALenum {
