> A small question about the patch, why this case in the cross_arch function:

From a real Mac Book Pro:

$ uname -a
Darwin MACBOOKPRO.local 11.4.2 Darwin Kernel Version 11.4.2: Thu Aug 23 16:25:48 PDT 2012; root:xnu-1699.32.7~1/RELEASE_X86_64 x86_64
$ /usr/bin/arch
i386
$ uname -m
x86_64

It would seem arch on OS X can only be used to determine PPC vs Intel (which is all that configure uses it for anyway).

> Why is cross-compiling to OSX useful at all?

Cross compiling is always useful for build engineers who have to target multiple hosts. 

> You still have to test if the output of the compilation works, and for that you need an OSX system.

Ideally yes, or a Virtual Machine with OSX on it or confidence based on the results of a previous test built with the same sources or maloader (...though maybe not, I've never personally tried maloader).

> The patch will only help with cross-compiling C code, it won't compile resource files (like the NIB file in Python Launcher)

My personal interest is for having Python embedded in other things (GDB) and using it from the command-line. Python Launcher is not part of the scope.

> This will make support harder, I already get support questions where the answer depends on the way Python was build and that will likely get worse with cross-compiling.

I'd be happy to do whatever I can to help out with this. If we could identify in the build that it was built via cross compilation somehow or have my email address in the help would that make it more palatable?

> * Where would users get the SDK? I'm not a lawyer (or even familiar with US law), but the Xcode license seems to indicate that it can only be used on Apple systems.

The users would get the SDK from being registered as a developer with Apple. As for the license, while also not being a lawyer, my interpretation is this:

In the Xcode License.rtf file (and the Command Line tools license), the relevant part is "you are granted a limited, non-exclusive license to use the Developer Software on Apple-branded computers to develop and test application and other software". This doesn't say anything about the OS that's running on said Apple-branded computer, and my interpretation is that you could install a Linux distro on an Apple computer or on a VM on an Apple computer and still be compliant with that license.