* doc/emacs/cmdargs.texi (Misc Variables): Add WAYLAND_DISPLAY
description.
the network library at startup, instead of waiting until the first
time it is required.
+@item WAYLAND_DISPLAY
+Pgtk Emacs (built with @option{--with-pgtk}) can run on Wayland natively.
+@env{WAYLAND_DISPLAY} specifies the connection to the compositor.
+
@item emacs_dir
On MS-Windows, @env{emacs_dir} is a special environment variable, which
indicates the full path of the directory in which Emacs is installed.