Move friend declarations into private class sections.

And hide them from Doxygen so it's not complaining. Related bug:
https://bugzilla.gnome.org/show_bug.cgi?id=776986

src/Magnum/AbstractResourceLoader.h

@@ -101,8 +101,6 @@ Resource<Mesh> myMesh = manager->get<Mesh>("my-mesh");
     buffers), should that be allowed?
 */
 template<class T> class AbstractResourceLoader {
-    friend Implementation::ResourceManagerData<T>;
-
     public:
         explicit AbstractResourceLoader(): manager(nullptr), _requestedCount(0), _loadedCount(0), _notFoundCount(0) {}
 
@@ -213,6 +211,10 @@ template<class T> class AbstractResourceLoader {
         virtual void doLoad(ResourceKey key) = 0;
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Implementation::ResourceManagerData<T>;
+        #endif
+
         Implementation::ResourceManagerData<T>* manager;
         std::size_t _requestedCount,
             _loadedCount,

src/Magnum/Context.h

@@ -60,8 +60,6 @@ See also @ref Extensions namespace, which contain compile-time information
 about OpenGL extensions.
 */
 class MAGNUM_EXPORT Extension {
-    friend Context;
-
     public:
         /** @brief All extensions for given OpenGL version */
         static const std::vector<Extension>& extensions(Version version);
@@ -76,6 +74,10 @@ class MAGNUM_EXPORT Extension {
         constexpr const char* string() const { return _string; }
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Context;
+        #endif
+
         std::size_t _index;
         Version _requiredVersion;
         Version _coreVersion;
@@ -115,9 +117,6 @@ Arguments:
 
 */
 class MAGNUM_EXPORT Context {
-    friend Implementation::ContextState;
-    friend Platform::Context;
-
     public:
         #ifndef MAGNUM_TARGET_WEBGL
         /**
@@ -572,6 +571,11 @@ class MAGNUM_EXPORT Context {
         MAGNUM_LOCAL bool isCoreProfileInternal(Implementation::ContextState& state);
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Implementation::ContextState;
+        friend Platform::Context;
+        #endif
+
         explicit Context(NoCreateT, Int argc, const char** argv, void functionLoader());
 
         bool tryCreate();

src/Magnum/Platform/Screen.h

@@ -66,10 +66,6 @@ The following specialization are explicitly compiled into each particular
 -   @ref XEglApplication "BasicScreen<XEglApplication>"
 */
 template<class Application> class BasicScreen: private Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>> {
-    friend Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>>;
-    friend Containers::LinkedList<BasicScreen<Application>>;
-    friend BasicScreenedApplication<Application>;
-
     public:
         #ifdef DOXYGEN_GENERATING_OUTPUT
         /**
@@ -257,6 +253,12 @@ template<class Application> class BasicScreen: private Containers::LinkedListIte
         virtual void mouseMoveEvent(MouseMoveEvent& event);
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>>;
+        friend Containers::LinkedList<BasicScreen<Application>>;
+        friend BasicScreenedApplication<Application>;
+        #endif
+
         PropagatedEvents _propagatedEvents;
 };
 

src/Magnum/Platform/ScreenedApplication.h

@@ -97,10 +97,6 @@ The following specialization are explicitly compiled into each particular
 -   @ref XEglApplication "BasicScreenedApplication<XEglApplication>"
 */
 template<class Application> class BasicScreenedApplication: public Application, private Containers::LinkedList<BasicScreen<Application>> {
-    friend Containers::LinkedList<BasicScreen<Application>>;
-    friend Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>>;
-    friend BasicScreen<Application>;
-
     public:
         /**
          * @brief Default constructor
@@ -236,6 +232,12 @@ template<class Application> class BasicScreenedApplication: public Application,
         virtual void globalDrawEvent() = 0;
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Containers::LinkedList<BasicScreen<Application>>;
+        friend Containers::LinkedListItem<BasicScreen<Application>, BasicScreenedApplication<Application>>;
+        friend BasicScreen<Application>;
+        #endif
+
         /* The user is supposed to override only globalViewportEvent() and
            globalDrawEvent(), these implementations are dispatching the events
            to attached screens. */

src/Magnum/Resource.h

@@ -119,8 +119,6 @@ template<class T, class U = T>
 template<class T, class U>
 #endif
 class Resource {
-    friend Implementation::ResourceManagerData<T>;
-
     public:
         /**
          * @brief Default constructor
@@ -215,6 +213,10 @@ class Resource {
         }
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Implementation::ResourceManagerData<T>;
+        #endif
+
         Resource(Implementation::ResourceManagerData<T>* manager, ResourceKey key): manager(manager), _key(key), lastCheck(0), _state(ResourceState::NotLoaded), data(nullptr) {
             manager->incrementReferenceCount(key);
         }

src/Magnum/SceneGraph/AbstractFeature.h

@@ -156,10 +156,6 @@ template<UnsignedInt dimensions, class T> class AbstractFeature
     : private Containers::LinkedListItem<AbstractFeature<dimensions, T>, AbstractObject<dimensions, T>>
     #endif
 {
-    friend Containers::LinkedList<AbstractFeature<dimensions, T>>;
-    friend Containers::LinkedListItem<AbstractFeature<dimensions, T>, AbstractObject<dimensions, T>>;
-    template<class> friend class Object;
-
     public:
         /**
          * @brief Constructor
@@ -278,6 +274,12 @@ template<UnsignedInt dimensions, class T> class AbstractFeature
         /*@}*/
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Containers::LinkedList<AbstractFeature<dimensions, T>>;
+        friend Containers::LinkedListItem<AbstractFeature<dimensions, T>, AbstractObject<dimensions, T>>;
+        template<class> friend class Object;
+        #endif
+
         CachedTransformations _cachedTransformations;
 };
 

src/Magnum/SceneGraph/AbstractObject.h

@@ -89,10 +89,6 @@ template<UnsignedInt dimensions, class T> class AbstractObject
     : private Containers::LinkedList<AbstractFeature<dimensions, T>>
     #endif
 {
-    friend Containers::LinkedList<AbstractFeature<dimensions, T>>;
-    friend Containers::LinkedListItem<AbstractFeature<dimensions, T>, AbstractObject<dimensions, T>>;
-    friend AbstractFeature<dimensions, T>;
-
     public:
         /** @brief Matrix type */
         typedef MatrixTypeFor<dimensions, T> MatrixType;
@@ -272,6 +268,12 @@ template<UnsignedInt dimensions, class T> class AbstractObject
         /*@}*/
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Containers::LinkedList<AbstractFeature<dimensions, T>>;
+        friend Containers::LinkedListItem<AbstractFeature<dimensions, T>, AbstractObject<dimensions, T>>;
+        friend AbstractFeature<dimensions, T>;
+        #endif
+
         virtual AbstractObject<dimensions, T>* doScene() = 0;
         virtual const AbstractObject<dimensions, T>* doScene() const = 0;
 

src/Magnum/SceneGraph/Object.h

@@ -111,9 +111,6 @@ template<class Transformation> class Object: public AbstractObject<Transformatio
     , private Containers::LinkedList<Object<Transformation>>, private Containers::LinkedListItem<Object<Transformation>, Object<Transformation>>
     #endif
 {
-    friend Containers::LinkedList<Object<Transformation>>;
-    friend Containers::LinkedListItem<Object<Transformation>, Object<Transformation>>;
-
     public:
         /** @brief Matrix type */
         typedef MatrixTypeFor<Transformation::Dimensions, typename Transformation::Type> MatrixType;
@@ -360,6 +357,11 @@ template<class Transformation> class Object: public AbstractObject<Transformatio
     #endif
 
     private:
+        #ifndef DOXYGEN_GENERATING_OUTPUT /* https://bugzilla.gnome.org/show_bug.cgi?id=776986 */
+        friend Containers::LinkedList<Object<Transformation>>;
+        friend Containers::LinkedListItem<Object<Transformation>, Object<Transformation>>;
+        #endif
+
         Object<Transformation>* doScene() override final;
         const Object<Transformation>* doScene() const override final;