Preferences support for Carbon Emacs

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

Mac OS X has a customization mechanism called "preferences".

  http://developer.apple.com/documentation/MacOSX/Conceptual/BPRuntimeConfig/Concepts/UserPreferences.html

I've just installed some changes that enable Carbon Emacs to get
preferences through X Resources functions (like registry on W32).
Now users can use preferences in place of X Resources.

For example, adding a line

   Emacs.cursorType: bar

to ~/.Xresources in X11 corresponds to the execution of

   % defaults write org.gnu.Emacs Emacs.cursorType bar

in Carbon.  One can use boolean or numeric values as well as string
values.

   % defaults write org.gnu.Emacs Emacs.toolBar -bool off
   % defaults write org.gnu.Emacs Emacs.lineSpacing -int 3

Of course, you can directly edit your own
~/Library/Preferences/org.gnu.Emacs.plist with Property List Editor or
your favorite text editor :-)

I also added a function that reads arbitrary application preference
value and converts it a Lisp object.  For example, evaluation of
(mac-get-preference "AppleLanguages") results in an array ["ja" "en"
"fr" "de" ...] of strings in my environment.  Maybe this can be used
for setting up the default language environment at startup time.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp