Platform: don't store useless variable on Emscripten.

src/Platform/Sdl2Application.cpp

@@ -328,7 +328,11 @@ Sdl2Application::Configuration::Configuration():
     #ifndef CORRADE_TARGET_EMSCRIPTEN
     _title("Magnum SDL2 Application"),
     #endif
-    _size(800, 600), _windowFlags(WindowFlag::Resizable), _sampleCount(0), _version(Version::None) {}
+    _size(800, 600), _windowFlags(WindowFlag::Resizable), _sampleCount(0)
+    #ifndef CORRADE_TARGET_EMSCRIPTEN
+    , _version(Version::None)
+    #endif
+    {}
 
 Sdl2Application::Configuration::~Configuration() = default;
 

src/Platform/Sdl2Application.h

@@ -538,7 +538,9 @@ class Sdl2Application::Configuration {
         Vector2i _size;
         WindowFlags _windowFlags;
         Int _sampleCount;
+        #ifndef CORRADE_TARGET_EMSCRIPTEN
         Version _version;
+        #endif
 };
 
 CORRADE_ENUMSET_OPERATORS(Sdl2Application::Configuration::WindowFlags)