Documentation work

Added missing documentation for Wayland dependencies and extensions.

docs/compat.dox

@@ -86,6 +86,38 @@ extension or there is no running compositing manager, the
 `GLFW_TRANSPARENT_FRAMEBUFFER` framebuffer hint will have no effect.
 
 
+@section compat_wayland Wayland protocols and IPC standards
+
+As GLFW uses libwayland directly, without any intervening toolkit library, it
+has sole responsibility for interacting well with every compositor in use on
+Unix-like systems.  Most of the features are provided by the core protocol,
+while cursor support is provided by the libwayland-cursor helper library, EGL
+integration by libwayland-egl, and keyboard handling by
+[libxkbcommon](https://xkbcommon.org/).  In addition, GLFW uses some protocols
+from wayland-protocols to provide additional features if the compositor
+supports them.
+
+GLFW uses xkbcommon 0.5.0 to provide compose key support.  When it has been
+built against an older xkbcommon, the compose key will be disabled even if it
+has been configured in the compositor.
+
+GLFW uses the [relative pointer
+protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/relative-pointer/relative-pointer-unstable-v1.xml)
+alongside the [pointer constraints
+protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/pointer-constraints/pointer-constraints-unstable-v1.xml)
+to implement disabled cursor.  These two protocols are part of
+wayland-protocols 1.1, and mandatory at build time.  If the running compositor
+does not support both of these protocols, disabling the cursor will have no
+effect.
+
+GLFW uses the [idle inhibit
+protocol](https://cgit.freedesktop.org/wayland/wayland-protocols/tree/unstable/idle-inhibit/idle-inhibit-unstable-v1.xml)
+to prohibit the screensaver from starting.  This protocol is part of
+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.
+
+
 @section compat_glx GLX extensions
 
 The GLX API is the default API used to create OpenGL contexts on Unix-like