updated: README.osx with two-liner to automate port installation

git-svn-id: https://xbmc.svn.sourceforge.net/svnroot/xbmc/branches/linuxport/XBMC@20320 568bbfeb-2a22-0410-94d2-cc84cf5bfa90

README.osx

@@ -150,6 +150,12 @@ Then install the following port packages (order is very important):
  $ sudo port install libsdl_mixer +universal
  $ sudo port install libsdl_image +universal
 
+If you understand the following two lines, you can run it to automate
+the installation of the ports in the above order:
+
+  sudo bash
+  cat README.osx | perl -ne 'print `port install $1` if /^ \$ sudo port install (.*)$/;'
+
 Finally, fix the mysql package default install location with this symlink:
 
  $ sudo ln -s /opt/local/include/mysql5/mysql/ /opt/local/include/mysql