Wayland: Allow using the --class to set the app id

Fixes #862

kitty/cli.py

@@ -464,7 +464,7 @@ def options_spec():
 dest=cls
 default={appname}
 condition=not is_macos
-Set the class part of the :italic:`WM_CLASS` window property
+Set the class part of the :italic:`WM_CLASS` window property. On Wayland, it sets the app id.
 
 
 --name

kitty/glfw-wrapper.h

@@ -745,6 +745,8 @@ typedef int (* GLFWapplicationshouldhandlereopenfun)(int);
 
 #define GLFW_X11_CLASS_NAME         0x00024001
 #define GLFW_X11_INSTANCE_NAME      0x00024002
+
+#define GLFW_WAYLAND_APP_ID         0x00025001
 /*! @} */
 
 #define GLFW_NO_API                          0

kitty/glfw.c

@@ -409,6 +409,7 @@ create_os_window(PyObject UNUSED *self, PyObject *args) {
 #ifndef __APPLE__
     glfwWindowHintString(GLFW_X11_INSTANCE_NAME, wm_class_name);
     glfwWindowHintString(GLFW_X11_CLASS_NAME, wm_class_class);
+    glfwWindowHintString(GLFW_WAYLAND_APP_ID, wm_class_class);
     if (OPT(x11_hide_window_decorations)) {
         glfwWindowHint(GLFW_DECORATED, GLFW_FALSE);
     }