Changes

TeXShop, once open again, will show a new available engine (the one you need) in the engine menu of the document window (named XeConTeXt, after the engine filename). The code in the engine file specifies a path where the shell should find texexec: <tt>/usr/texbin</tt> is the standard on MacTeX, but of course you have to check the path on your system. Important note: it has been reported that the XeConTeXt.engine file must contain a blank line (as in the example), otherwise the program will stalls stall (dont't ask...).