# download xcode

https://developer.apple.com/downloads/index.action

# extract xcode (from linux)

dmg2img -p 5 xcode_6.0.1.dmg
sudo mount -t hfsplus -o loop xcode_6.0.1.img /mnt

mkdir -p /opt/osx/sysroot
cp -a /mnt/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/* /opt/osx/sysroot
cp -r /opt/osx/sysroot/usr/lib/system/* /opt/osx/sysroot/usr/lib

# extract xcode (from osx)

hdiutil attach xcode_6.0.1.dmg

mkdir -p /opt/osx/sysroot # on linux
cp -a /n/osx/Volumes/Xcode/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/* /opt/osx/sysroot # on linux
cp -r /opt/osx/sysroot/usr/lib/system/* /opt/osx/sysroot/usr/lib # on linux

hdiutil detach /Volumes/Xcode

# cctools-port

cd /opt/osx

git clone https://github.com/tpoechtrager/cctools-port

cd cctools-port/cctools
DISABLE_LTO_SUPPORT=1 ./autogen.sh
patch -p1 < /tmp/cctools.diff
./configure --prefix=/opt/osx --target=x86_64-apple-darwin
make
make install

# environment

export PATH=$PATH:/opt/osx/bin

# gcc

cd /opt/osx

wget ftp://ftp.lip6.fr/pub/gcc/releases/gcc-4.8.3/gcc-4.8.3.tar.bz2
tar xjvf gcc-4.8.3.tar.bz2
cd gcc-4.8.3
./contrib/download_prerequisites
ln -s /bin/m4 /bin/m4-not-needed
mkdir build
cd build
../configure --prefix=/opt/osx --disable-checking --enable-languages=c --with-as=/opt/osx/bin/x86_64-apple-darwin-as --with-ld=/opt/osx/bin/x86_64-apple-darwin-ld --target=x86_64-apple-darwin --with-sysroot=/opt/osx/sysroot/ --disable-nls --enable-multilib --disable-libssp --enable-static --enable-shared --disable-libgomp
RC_ProjectName="" MACOSX_DEPLOYMENT_TARGET="" make
RC_ProjectName="" MACOSX_DEPLOYMENT_TARGET="" make install