https://github.com/tatsh/xchain
I have successfully created multiple compilers (both regular GCC and LLVM-GCC) targeting the following triples: arm-apple-darwin* (iOS only) i686-apple-darwin* x86_64-apple-darwin* I have not tried powerpc or powerpc64 yet but I think they will work, if not then with minimal changes that still keep everything else working. Most sources come from http://opensource.apple.com just like the sys-devel/binutils-apple and sys-devel/gcc-apple packages. The version of cctools in the project is patched heavily (mainly due to missing headers, which we can distribute). One source is derived from iphone-dev's version of odcctools, but only for one part of it (ld64). It is not the same and needed fixing to compile with GCC 4.5.3. I plan to fix the up-to-date ld64 regardless. Their ar and ranlib is VERY sensitive to any optimisation flags and basically chokes on building GCC if you built with any flags like -O2, etc. https://github.com/tatsh/xchain/blob/master/cctools-806/ar/archive.c https://github.com/tatsh/xchain/blob/master/cctools-806/misc/ranlib.c lines Any calls to sprintf are in question. The real caveat is how to get the SDK headers and libs. I haven't checked but I think everything is under APSL, but I don't know the legality of creating a custom tarball. I tested everything with the latest you can get (that's not under NDA), which is Xcode 4.1.1 from the Mac App Store (it is free). You cannot get this from anywhere else. You can get Xcode 3.2.6 from Apple's developer site for free, but that requires login. It cannot be automatically downloaded. Plus I do not know when it will disappear (I'm betting soon). So the easiest way IMO is to just install Xcode and scp. scp -r myname@mymac:/Developer/SDKs/MacOSX10.7.sdk . scp -r myname@mymac:/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS4.3.sdk . These are directories and are essentially the sysroot. usr is in them and should be where any new things like gcc, ar, etc go into. By default, if x86 or powerpc, everything compiled runs on 10.4u and up. It is even possible to create fat binaries with lipo (although I have only tried this with ARM and x86_64). Any x86_64 code requires 10.5 or higher. For iOS, I believe you can specify as low as 1.0 for iOS minimum but the only sure way to actually ensure it would run is to use such an SDK. Obviously the iOS code here is not signed, you would need to do that on your Mac with the `codesign` utility. You can do half the work on Linux with the `codesign_allocate` which just makes space for the signing information. If you have a jailbroken device, all code will run as is without needing to sign. Finally, both LLVM GCC and regular GCC will work. The instructions for this are in the README. I'd like to reach the point of being able to type (perhaps with prerequisite work done by me like copying the SDK) `crossdev -t arm-apple-darwin` and `crossdev -t arm-apple-darwinX` (where X is 9, 10, 11).
