Add virtual deconstructor override

Virtual classes need to override the base-type deconstructor so that they are proper called when referred to by their base-type.

include/renderer_gl/renderer_gl.hpp

@@ -68,6 +68,7 @@ class RendererGL final : public Renderer {
 
   public:
 	RendererGL(GPU& gpu, const std::array<u32, regNum>& internalRegs) : Renderer(gpu, internalRegs) {}
+	~RendererGL() override;
 
 	void reset() override;
 	void display() override;                                                              // Display the 3DS screen contents to the window

src/core/renderer_gl/renderer_gl.cpp

@@ -14,6 +14,8 @@ using namespace Floats;
 using namespace Helpers;
 using namespace PICA;
 
+RendererGL::~RendererGL() {}
+
 void RendererGL::reset() {
 	depthBufferCache.reset();
 	colourBufferCache.reset();