Platform: properly fire Sdl2Application::viewportEvent() in all cases.

The event wasn't fired when the window size got changed through an API
call. Unfortunately after this change the event gets fired any time
I call setMaxWindowSize(), not just when the size changes.

doc/changelog.dox

@@ -98,6 +98,9 @@ See also:
 
 @subsection changelog-latest-bugfixes Bug fixes
 
+-   @ref Platform::Sdl2Application::viewportEvent() gets properly fired also
+    when window size changes programmatically (such as through
+    @ref Platform::Sdl2Application::setMinWindowSize() "setMinWindowSize()")
 -   The @ref Primitives::cylinderSolid() and @ref Primitives::coneSolid()
     primitives were missing a face when both caps and texture coordinates were
     enabled (see [mosra/magnum#386](https://github.com/mosra/magnum/issues/386))

src/Magnum/Platform/Sdl2Application.cpp

@@ -755,7 +755,10 @@ bool Sdl2Application::mainLoopIteration() {
         switch(event.type) {
             case SDL_WINDOWEVENT:
                 switch(event.window.event) {
-                    case SDL_WINDOWEVENT_RESIZED: {
+                    /* Not using SDL_WINDOWEVENT_RESIZED, because that doens't
+                       get fired when the window is resized programmatically
+                       (such as through setMaxWindowSize()) */
+                    case SDL_WINDOWEVENT_SIZE_CHANGED: {
                         #ifdef CORRADE_TARGET_EMSCRIPTEN
                         /* If anybody sees this assert, then emscripten finally
                            implemented resize events. Praise them for that.