Update Mac specific README files

README_extra.txt

@@ -22,8 +22,10 @@ src/os_beos.*		Files for the BeOS port.
 src/os_msdos.*
 src/os_dos.*		Files for the MS-DOS port.
 
-src/gui_mac.*
-src/os_mac.*		Files for the Mac port.
+src/gui_mac.*           Carbon GUI (not used)
+src/os_mac*		Shared files for the different Mac ports.
+
+src/MacVim/*		Files for the MacVim port.
 
 src/os_mint.8		Files for the Atari Mint port.
 

README_mac.txt

@@ -1,8 +1,37 @@
 README_mac.txt for version 7.3 of Vim: Vi IMproved.
 
-This file explains the installation of Vim on Macintosh systems.
+This file explains the installation of MacVim.
 See "README.txt" for general information about Vim.
+See "src/MacVim/README" for an overview of the MacVim specific source code.
 
+MacVim uses the usual configure/make steps to build the binary but instead of
+"make install" you just drag the app bundle into the directory you wish to
+install in (usually `/Applications').
 
-Sorry, this text still needs to be written!
 
+How to build and install
+========================
+
+Run `./configure` in the `src/` directory with the flags you want, e.g.:
+
+    $ cd src
+    $ ./configure --with-features=huge \
+                  --enable-rubyinterp \
+                  --enable-pythoninterp \
+                  --enable-perlinterp \
+                  --enable-cscope
+
+Now build the project using `make`:
+
+    $ make
+
+The resulting app bundle will reside under `MacVim/build/Release`.  To try it
+out quickly, type:
+
+    $ open MacVim/build/Release/MacVim.app
+
+To install MacVim, type
+
+    $ open MacVim/build/Release
+
+and drag the MacVim icon into your `Applications` folder.