DebugTools: fix a linker error on Clang.

Not sure why it started happening only after I added a deprecated
constructor. Making it the same as is done for Image classes.

src/Magnum/DebugTools/ForceRenderer.cpp

@@ -92,7 +92,7 @@ template<UnsignedInt dimensions> void ForceRenderer<dimensions>::draw(const Matr
     _mesh->draw(*_shader);
 }
 
-template class ForceRenderer<2>;
-template class ForceRenderer<3>;
+template class MAGNUM_DEBUGTOOLS_EXPORT ForceRenderer<2>;
+template class MAGNUM_DEBUGTOOLS_EXPORT ForceRenderer<3>;
 
 }}

src/Magnum/DebugTools/ForceRenderer.h

@@ -118,7 +118,7 @@ to it.
 
 @see @ref ForceRenderer2D, @ref ForceRenderer3D, @ref ForceRendererOptions
 */
-template<UnsignedInt dimensions> class MAGNUM_DEBUGTOOLS_EXPORT ForceRenderer: public SceneGraph::Drawable<dimensions, Float> {
+template<UnsignedInt dimensions> class ForceRenderer: public SceneGraph::Drawable<dimensions, Float> {
     public:
         /**
          * @brief Constructor

src/Magnum/DebugTools/ObjectRenderer.cpp

@@ -79,7 +79,7 @@ template<UnsignedInt dimensions> void ObjectRenderer<dimensions>::draw(const Mat
     _mesh->draw(*_shader);
 }
 
-template class ObjectRenderer<2>;
-template class ObjectRenderer<3>;
+template class MAGNUM_DEBUGTOOLS_EXPORT ObjectRenderer<2>;
+template class MAGNUM_DEBUGTOOLS_EXPORT ObjectRenderer<3>;
 
 }}

src/Magnum/DebugTools/ObjectRenderer.h

@@ -90,7 +90,7 @@ Example code:
 
 @see @ref ObjectRenderer2D, @ref ObjectRenderer3D, @ref ObjectRendererOptions
 */
-template<UnsignedInt dimensions> class MAGNUM_DEBUGTOOLS_EXPORT ObjectRenderer: public SceneGraph::Drawable<dimensions, Float> {
+template<UnsignedInt dimensions> class ObjectRenderer: public SceneGraph::Drawable<dimensions, Float> {
     public:
         /**
          * @brief Constructor