Platform: properly propagate return code from WindowlessWglApplication.

src/Magnum/Platform/WindowlessWglApplication.cpp

@@ -51,7 +51,10 @@ int WindowlessWglApplication::create(LRESULT(CALLBACK windowProcedure)(HWND, UIN
     CreateWindowW(wc.lpszClassName, L"Magnum Windowless Application",
         WS_OVERLAPPEDWINDOW, 0, 0, 32, 32, 0, 0, wc.hInstance, 0);
 
-    return 0;
+    /* Hammer the return code out of the messaging thingy */
+    MSG msg;
+    do {} while(GetMessageW(&msg, nullptr, 0, 0) != 0);
+    return msg.wParam;
 }
 #endif
 

src/Magnum/Platform/WindowlessWglApplication.h

@@ -195,9 +195,8 @@ windowless application header is included this macro is also aliased to
             case WM_CREATE:                                                 \
                 {                                                           \
                     className app({globalArgc, globalArgv, hWnd});          \
-                    app.exec();                                             \
+                    PostQuitMessage(app.exec());                            \
                 }                                                           \
-                PostQuitMessage(0);                                         \
                 break;                                                      \
             default: return DefWindowProc(hWnd, message, wParam, lParam);   \
         }                                                                   \