Math: avoid std::tie() in DualQuaternion sclerp..

It needs #include <tuple> and that's heavier than I'd like.

src/Magnum/Math/DualQuaternion.h

@@ -103,9 +103,8 @@ template<class T> inline DualQuaternion<T> sclerp(const DualQuaternion<T>& norma
     const Dual<Vector3<T>> n{direction, moment};
 
     /* q_ScLERP = q_A*(cos(t*a/2) + n*sin(t*a/2)) */
-    Dual<T> sin, cos;
-    std::tie(sin, cos) = Math::sincos(t*Dual<Rad<T>>(aHalf));
-    return normalizedA*DualQuaternion<T>{n*sin, cos};
+    const std::pair<Dual<T>, Dual<T>> sincos = Math::sincos(t*Dual<Rad<T>>(aHalf));
+    return normalizedA*DualQuaternion<T>{n*sincos.first, sincos.second};
 }
 
 /** @relatesalso DualQuaternion
@@ -170,9 +169,8 @@ template<class T> inline DualQuaternion<T> sclerpShortestPath(const DualQuaterni
     const Dual<Vector3<T>> n{direction, moment};
 
     /* q_ScLERP = q_A*(cos(t*a/2) + n*sin(t*a/2)) */
-    Dual<T> sin, cos;
-    std::tie(sin, cos) = Math::sincos(t*Dual<Rad<T>>(aHalf));
-    return normalizedA*DualQuaternion<T>{n*sin, cos};
+    const std::pair<Dual<T>, Dual<T>> sincos = Math::sincos(t*Dual<Rad<T>>(aHalf));
+    return normalizedA*DualQuaternion<T>{n*sincos.first, sincos.second};
 }
 
 /**