Add selection of custom input areas on Wayland.

Automatic and correct input mapping on Wayland is difficult/impossible.
Thus, on Wayland Weylus now supports the selection of a custom input
area. This is done via a pop-up window that is positioned according to
the desired area of input. Typically, the different input devices
(mouse, touch, pen) can be mapped to the whole workspace (all screens)
or only a specific screen. KDE for example offers input mapping of touch
input to a specific screen. To Weylus this specific mapping is not know
and needs to be specified in a choice menu of the pop-up window.

lib/linux/xhelper.c

@@ -21,7 +21,8 @@ int x11_error_handler(Display* disp, XErrorEvent* err)
 	return 0;
 }
 
-void x11_set_error_handler() {
+void x11_set_error_handler()
+{
 	// setting an error handler is required as otherwise xlib may just exit the process, even though
 	// the error was recoverable.
 	XSetErrorHandler(x11_error_handler);
@@ -176,7 +177,8 @@ Window* get_client_list(Display* disp, unsigned long* size, Error* err)
 	return client_list;
 }
 
-int create_capturables(Display* disp, Capturable** capturables, int* num_monitors, int size, Error* err)
+int create_capturables(
+	Display* disp, Capturable** capturables, int* num_monitors, int size, Error* err)
 {
 	if (size <= 0)
 		return 0;

src/capturable/mod.rs

@@ -7,6 +7,7 @@ pub mod core_graphics;
 #[cfg(target_os = "linux")]
 pub mod pipewire;
 #[cfg(target_os = "linux")]
+#[allow(dead_code)]
 pub mod remote_desktop_dbus;
 pub mod testsrc;
 
@@ -37,6 +38,7 @@ where
 /// VirtualScreen: offset_x, offset_y, width, height for a capturable using a virtual screen. (Windows)
 pub enum Geometry {
     Relative(f64, f64, f64, f64),
+    #[cfg(target_os = "windows")]
     VirtualScreen(i32, i32, u32, u32, i32, i32),
 }