Reset dead keys when the SDL window loses focus, so dead keys pressed in SDL applications don't affect text input into other applications.

src/video/windows/SDL_windowsevents.c

@@ -451,6 +451,7 @@ WIN_WindowProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
 
                 if (SDL_GetKeyboardFocus() == data->window) {
                     SDL_SetKeyboardFocus(NULL);
+                    WIN_ResetDeadKeys();
                 }
 
                 ClipCursor(NULL);

src/video/windows/SDL_windowskeyboard.c

@@ -165,7 +165,6 @@ WIN_ResetDeadKeys()
     this tries to undo the effect pressing the deadkey.
     see: http://archives.miloush.net/michkap/archive/2006/09/10/748775.html
     */
-
     BYTE keyboardState[256];
     WCHAR buffer[16];
     int keycode, scancode, result, i;
@@ -174,17 +173,14 @@ WIN_ResetDeadKeys()
 
     keycode = VK_SPACE;
     scancode = MapVirtualKey(keycode, MAPVK_VK_TO_VSC);
-    if (scancode == 0)
-    {
+    if (scancode == 0) {
         /* the keyboard doesn't have this key */
         return;
     }
 
-    for (i = 0; i < 5; i++)
-    {
+    for (i = 0; i < 5; i++) {
         result = ToUnicode(keycode, scancode, keyboardState, (LPWSTR)buffer, 16, 0);
-        if (result > 0)
-        {
+        if (result > 0) {
             /* success */
             return;
         }

src/video/windows/SDL_windowskeyboard.h

@@ -27,6 +27,8 @@ extern void WIN_InitKeyboard(_THIS);
 extern void WIN_UpdateKeymap(void);
 extern void WIN_QuitKeyboard(_THIS);
 
+extern void WIN_ResetDeadKeys(void);
+
 extern void WIN_StartTextInput(_THIS);
 extern void WIN_StopTextInput(_THIS);
 extern void WIN_SetTextInputRect(_THIS, SDL_Rect *rect);