Re: Cross Compiling for OS X?

[David Chisnall]

On 3 May 2008, at 10:26, hns@computer.org wrote:

> c) Real cross-compiling
> This means that you have a gcc version on your Linux machine that
> emits executables that run on OSX. Unfortunately, OSX uses MACH-O
> binaries and building a cross-compiling gcc is very tricky.

I've not tried building Apple GCC on non-Apple platforms, but even if  
you do this then you need more to get a real cross-compiling  
environment.  You also need copies of every header file that your  
program includes.  You can't substitute GNUstep's Foundation.h for  
Apple's, since they have different instance variable layouts so any of  
your subclasses of Apple classes will be wrong.  This header also  
includes other headers which define things like the sizes and layouts  
of of C types and so on,   These can be acquired from the Darwin  
sources, but you'll still need the framework headers which are not  
publicly redistributable.  In short, cross compiling is hard, which is  
why hardly anyone does it.

Improving GNUstep Make to build native OS X applications (it already  
works nicely for frameworks) would be a better approach, but I'm not  
sure how much effort this would be.  Building OS X apps from a  
makefile isn't very hard, although fat binaries are slightly harder,  
so it might be worth investigating.

David