>Compiling would take ages and kill the battery.
It doesnt make sense to include all the features/toolkit parts for an embedded OS when you can easily cross-compile and test your code on simulators.
>However if you had to run Windows to compile Mac OS
You should be able to cross compile MacOS on a windows host... MacOS should also have the tools to compile itself and crosscompile for any interesting targets (iPhone etc)... MacOS isn't an embedded os though.
