Unlikely to work yet, but at least builds for the simulator.

We can not use dynamic code generation on iOS, so we use a fixed set
of code snippets, genertated by a Perl script. Experimentation seems
to indicate that a relatively small set of static code snippets should
be enough in simple use cases with no extensions (that we can't really
support on iOS anyway) and stuff.

Except for the static set of snippets the code mostly is, or will be,
an ifdefified combination of the gcc3_linux_arm and gcc3_macosx_intel
code. The ABI on iOS ARM devices should be quite close to that on
Linux ARM, knock on wood.