Allow manual position for is_cursor_in_wine_window

We'll need this for the `LeaveNotify` because `GetCursorPos()` updates
only once every 100 ms, which means that it would still point to the old
window we're actually leaving.

src/wine-host/editor.cpp

@@ -1259,12 +1259,16 @@ ATOM get_window_class() noexcept {
     return window_class_handle;
 }
 
-bool is_cursor_in_wine_window() noexcept {
+bool is_cursor_in_wine_window(
+    std::optional<POINT> windows_pointer_pos) noexcept {
     static const HWND windows_desktop_window = GetDesktopWindow();
 
-    POINT windows_pointer_pos;
+    if (!windows_pointer_pos) {
-    GetCursorPos(&windows_pointer_pos);
+        windows_pointer_pos.emplace();
-    if (HWND windows_window = WindowFromPoint(windows_pointer_pos);
+        GetCursorPos(&*windows_pointer_pos);
+    }
+
+    if (HWND windows_window = WindowFromPoint(*windows_pointer_pos);
         windows_window && windows_window != windows_desktop_window) {
         // NOTE: Because resizing reparented Wine windows without XEmbed is a
         //       bit janky, yabridge creates windows with client areas large

src/wine-host/editor.h

@@ -75,8 +75,13 @@ xcb_atom_t get_atom_by_name(xcb_connection_t& x11_connection,
  * area of yabridge windows. (so it will consider other Wine windows to the
  * right or to the bottom of a yabridge plugin editor, but not the extended
  * client area itself)
+ *
+ * @param windows_pointer_pos The screen coordinates to use for the query. If
+ *   this is left at a nullopt, we will simply use `GetCursorPos()`. Note that
+ *   this value only updates once every 100 milliseconds.
  */
-bool is_cursor_in_wine_window() noexcept;
+bool is_cursor_in_wine_window(
+    std::optional<POINT> windows_pointer_pos = std::nullopt) noexcept;
 
 /**
  * Used to store the maximum width and height of a screen.