add constexpr to param qualifiers detection

alib2abstraction/src/common/ParamQualifiers.hpp

@@ -18,13 +18,13 @@ public:
 	static ext::set < ParamQualifier > paramQualifiers ( ) {
 		ext::set < ParamQualifier > res;
-		if ( std::is_lvalue_reference < Param >::value )
+		if constexpr ( std::is_lvalue_reference < Param >::value )
 			res.insert ( ParamQualifier::LREF );
-		if ( std::is_rvalue_reference < Param >::value )
+		if constexpr ( std::is_rvalue_reference < Param >::value )
 			res.insert ( ParamQualifier::RREF );
-		if ( std::is_const < typename std::remove_reference < Param >::type >::value )
+		if constexpr ( std::is_const < typename std::remove_reference < Param >::type >::value )
 			res.insert ( ParamQualifier::CONST );
 		return res;