No need to have virtual destructor in AbstractFramebuffer.

src/AbstractFramebuffer.cpp

@@ -47,8 +47,6 @@ FramebufferTarget AbstractFramebuffer::readTarget = FramebufferTarget::ReadDraw;
 FramebufferTarget AbstractFramebuffer::drawTarget = FramebufferTarget::ReadDraw;
 #endif
 
-AbstractFramebuffer::~AbstractFramebuffer() {}
-
 void AbstractFramebuffer::bind(FramebufferTarget target) {
     bindInternal(target);
     setViewportInternal();

src/AbstractFramebuffer.h

@@ -190,7 +190,6 @@ class MAGNUM_EXPORT AbstractFramebuffer {
         }
 
         explicit AbstractFramebuffer() = default;
-        virtual ~AbstractFramebuffer() = 0;
 
         /**
          * @brief Bind framebuffer for rendering
@@ -269,6 +268,8 @@ class MAGNUM_EXPORT AbstractFramebuffer {
     #else
     protected:
     #endif
+        ~AbstractFramebuffer() = default;
+
         void MAGNUM_LOCAL bindInternal(FramebufferTarget target);
         FramebufferTarget MAGNUM_LOCAL bindInternal();
         void MAGNUM_LOCAL setViewportInternal();