[propertysytem] Remove outdated macro-related check

dumux/common/properties/propertysystem.hh

@@ -50,16 +50,15 @@ template<class P>
 constexpr std::true_type isDefinedProperty(...) { return {}; }
 
 //! check if a TypeTag inherits from other TypeTags
-//! the enable_if portion of decltype is only needed for the macro hack to work, if no macros are in use anymore it can be removed,
-//! i.e. then trailing return type is then -> decltype(std::declval<typename T::InheritsFrom>(), std::true_type{})
 template<class T>
 constexpr auto hasParentTypeTag(int)
--> decltype(std::declval<typename T::InheritsFrom>(), std::enable_if_t<!std::is_same<typename T::InheritsFrom, void>::value, int>{}, std::true_type{})
+-> decltype(std::declval<typename T::InheritsFrom>(), std::true_type{})
 { return {}; }
 
 //! fall back if a TypeTag doesn't inherit
 template<class T>
-constexpr std::false_type hasParentTypeTag(...) { return {}; }
+constexpr std::false_type hasParentTypeTag(...)
+{ return {}; }
 
 //! helper alias to concatenate multiple tuples
 template<class ...Tuples>