Fix NS frame parameters (bug#39000)

* src/frame.c (make_frame): Use new system default setting.
* src/frame.h (enum ns_appearance_type): Add new system default
setting.
* src/nsfns.m (Fx_create_frame): Correctly handle Qunbound and support
system default appearance.
(syms_of_nsfns): Add Qlight.
* src/nsterm.h: New method definition.
* src/nsterm.m (ns_set_appearance): Correctly handle Qlight and use new
setAppearance method.
([EmacsView initFrameFromEmacs:]): Use new setAppearance method.
([EmacsWindow setAppearance]): New method.
* doc/lispref/frames.texi (Management Parameters): Document 'light'.

1 files changed, 5 insertions, 4 deletions

diff --git a/doc/lispref/frames.texi b/doc/lispref/frames.texi
index 05038c6f52b..9bd8bedc660 100644
--- a/doc/lispref/frames.texi
+++ b/doc/lispref/frames.texi
@@ -2192,10 +2192,11 @@ it and see if it works.)
 @vindex ns-appearance@r{, a frame parameter}
 @item ns-appearance
 Only available on macOS, if set to @code{dark} draw this frame's
-window-system window using the ``vibrant dark'' theme, otherwise use
-the system default.  The ``vibrant dark'' theme can be used to set the
-toolbar and scrollbars to a dark appearance when using an Emacs theme
-with a dark background.
+window-system window using the ``vibrant dark'' theme, and if set to
+@code{light} use the ``aqua'' theme, otherwise use the system default.
+The ``vibrant dark'' theme can be used to set the toolbar and
+scrollbars to a dark appearance when using an Emacs theme with a dark
+background.
 
 @vindex ns-transparent-titlebar@r{, a frame parameter}
 @item ns-transparent-titlebar