CrossCompilingOsX

This is being worked on, please maintain your patience. I have successfully done this before but I don't remember what I did, so I will have to recreate a lot of stuff.

You need:

• a mind so deadset on cross-compiling you won't stop to think
• the Xcode .dmg for your target OS X version
• root access to your build system
• a good processor and a lot of RAM

I used Ubuntu 14.04 "Trusty Tahr" for doing the initial chroot. The process was as follows:

apt-get install dchroot debootstrap

Then edit /etc/schroot/schroot.conf with your favourite text editor, and add this at the end:

[trusty]
description=Ubuntu Trusty
location=/var/chroot
priority=3
users=your_username
groups=sbuild
root-groups=root

Install a base system:

sudo debootstrap --variant=buildd --arch amd64 trusty /var/chroot/ mirror.url.com/ubuntu/

where mirror.url.com/ubuntu/ can be any of these mirrors.

Now copy your resolv.conf for internet access (required):

sudo cp /etc/resolv.conf /var/chroot/etc/resolv.conf

Bind your procfs into the chroot for gnustep:

sudo mount -o bind /proc /var/chroot/proc

Finally, chroot into your target:

sudo chroot /var/chroot

You should now have a working chroot, free for you to destroy as you see fit. (from https://help.ubuntu.com/community/BasicChroot)

To avoid pointless warnings about missing locales, do this:

apt-get install language-pack-en

Install some packages to start off with:

apt-get install sudo nano vim bzr subversion

Edit your /etc/apt/sources.list to include the universe source and update:

deb mirror.url.com/ubuntu/ trusty main
deb-src mirror.url.com/ubuntu/ trusty main

deb mirror.url.com/ubuntu/ trusty universe
deb-src mirror.url.com/ubuntu/ trusty universe

Now install gnustep:

apt-get install gnustep gnustep-devel

This may take a while.

Next, we're going to build clang, llvm, and libc++ that target OS X.

cd /usr/src
svn co http://llvm.org/svn/llvm-project/llvm/trunk llvm
cd llvm/tools
svn co http://llvm.org/svn/llvm-project/cfe/trunk clang
cd ..; mkdir build; cd build
../configure --prefix=/usr/clang_3_4 --enable-optimized --enable-targets=x86_64-apple-darwin11.4.2 \
   --disable-compiler-version-checks --host=x86_64-unknown-linux-gnu --build=x86_64-unknown-linux-gnu \
   --target=x86_64-apple-darwin11.4.2
make -j4
make install

Next step: APSL headers for OSX, from Xcode, and then add libc++ compile instructions

More coming...