Add nil dtor for window, and make it ready for C++

src/bw.cc

@@ -21,6 +21,7 @@
 #include "capi.hh"
 #include "uicmd.hh"
 
+BrowserWindow::~BrowserWindow()= default;
 
 /*
  * Local Data

src/bw.hh

@@ -24,7 +24,7 @@
 
 
 /** Contains the specific data for a single window */
-typedef struct {
+struct BrowserWindow {
    /** Pointer to the UI object this bw belongs to */
    void *ui;
 
@@ -72,11 +72,15 @@ typedef struct {
 
    /* Zoom factor */
    float zoom;
-} BrowserWindow;
+
+   ~BrowserWindow();
+};
 
 
 #ifdef __cplusplus
 extern "C" {
+#else
+#error Browser Window is C++ now.
 #endif /* __cplusplus */