Documentation work

Describe glfw#1341.

docs/compat.dox

@@ -126,13 +126,18 @@ wayland-protocols 1.6, and mandatory at build time.  If the running compositor
 does not support this protocol, the screensaver may start even for full screen
 windows.
 
-GLFW uses the [viewporter
+GLFW uses the [xdg-decoration
+protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/xdg-decoration/xdg-decoration-unstable-v1.xml)
+to request decorations to be drawn around its windows.  This protocol is part
+of wayland-protocols 1.15, and mandatory at build time.  If the running
+compositor does not support this protocol, a very simple frame will be drawn by
+GLFW itself, using the [viewporter
 protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/stable/viewporter/viewporter.xml)
 alongside
-[subsurfaces](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n2598)
-to draw decorations around windows.  This protocol is part of wayland-protocols
-1.4, and mandatory at build time.  If the running compositor does not support
-this protocol, no decorations will be drawn around windows.
+[subsurfaces](https://cgit.freedesktop.org/wayland/wayland/tree/protocol/wayland.xml#n2598).
+This protocol is part of wayland-protocols 1.4, and mandatory at build time.
+If the running compositor does not support this protocol either, no decorations
+will be drawn around windows.
 
 
 @section compat_glx GLX extensions

include/GLFW/glfw3.h

@@ -2478,11 +2478,13 @@ GLFWAPI void glfwWindowHintString(int hint, const char* value);
  *  GLFW_X11_CLASS_NAME and @ref GLFW_X11_INSTANCE_NAME window hints to override
  *  this.
  *
- *  @remark @wayland The window frame is currently very simple, only allowing
- *  window resize or move.  A compositor can still emit close, maximize or
- *  fullscreen events, using for example a keybind mechanism.  Additionally,
- *  the wp_viewporter protocol is required for this feature, otherwise the
- *  window will not be decorated.
+ *  @remark @wayland Compositors should implement the xdg-decoration protocol
+ *  for GLFW to decorate the window properly.  If this protocol isn't
+ *  supported, or if the compositor prefers client-side decorations, a very
+ *  simple fallback frame will be drawn using the wp_viewporter protocol.  A
+ *  compositor can still emit close, maximize or fullscreen events, using for
+ *  instance a keybind mechanism.  If neither of these protocols is supported,
+ *  the window won't be decorated.
  *
  *  @remark @wayland A full screen window will not attempt to change the mode,
  *  no matter what the requested size or refresh rate.