Zero initialize all pointer class and struct members

This prevents the pitfall of UB when checking if they have been
assigned something valid by comparing to nullptr.

platform/linuxbsd/display_server_x11.h

@@ -108,7 +108,7 @@ class DisplayServerX11 : public DisplayServer {
 #endif
 
 #if defined(DBUS_ENABLED)
-	FreeDesktopScreenSaver *screensaver;
+	FreeDesktopScreenSaver *screensaver = nullptr;
 	bool keep_screen_on = false;
 #endif
 
@@ -168,7 +168,7 @@ class DisplayServerX11 : public DisplayServer {
 	String internal_clipboard_primary;
 	Window xdnd_source_window;
 	::Display *x11_display;
-	char *xmbstring;
+	char *xmbstring = nullptr;
 	int xmblen;
 	unsigned long last_timestamp;
 	::Time last_keyrelease_time;
@@ -249,7 +249,7 @@ class DisplayServerX11 : public DisplayServer {
 	typedef void (*xrr_free_monitors_t)(xrr_monitor_info *monitors);
 	xrr_get_monitors_t xrr_get_monitors;
 	xrr_free_monitors_t xrr_free_monitors;
-	void *xrandr_handle;
+	void *xrandr_handle = nullptr;
 	Bool xrandr_ext_ok;
 
 	struct Property {

platform/linuxbsd/gl_manager_x11.h

@@ -66,7 +66,7 @@ private:
 	struct GLDisplay {
 		GLDisplay() { context = nullptr; }
 		~GLDisplay();
-		GLManager_X11_Private *context;
+		GLManager_X11_Private *context = nullptr;
 		::Display *x11_display;
 		XVisualInfo x_vi;
 		XSetWindowAttributes x_swa;
@@ -82,7 +82,7 @@ private:
 	LocalVector<GLWindow> _windows;
 	LocalVector<GLDisplay> _displays;
 
-	GLWindow *_current_window;
+	GLWindow *_current_window = nullptr;
 
 	void _internal_set_current_window(GLWindow *p_win);
 

platform/linuxbsd/os_linuxbsd.h

@@ -63,7 +63,7 @@ class OS_LinuxBSD : public OS_Unix {
 
 	CrashHandler crash_handler;
 
-	MainLoop *main_loop;
+	MainLoop *main_loop = nullptr;
 
 protected:
 	virtual void initialize() override;