improve WGPU / GLFW / Wayland story by weak linking and adjusting docs

vendor/glfw/native_linux.odin

@@ -13,7 +13,13 @@ foreign {
 	SetX11SelectionString :: proc(string:  cstring) ---
 	GetX11SelectionString :: proc() -> cstring ---
 
+	// Functions added in 3.4, Linux links against system glfw so we define these as weak to be able
+	// to check at runtime if they are available.
+
+	@(linkage="weak")
 	GetWaylandDisplay :: proc()                       -> rawptr /* struct wl_display* */ ---
+	@(linkage="weak")
 	GetWaylandWindow  :: proc(window:  WindowHandle)  -> rawptr /* struct wl_surface* */ ---
+	@(linkage="weak")
 	GetWaylandMonitor :: proc(monitor: MonitorHandle) -> rawptr /* struct wl_output*  */ ---
 }