To build the unstable (working-in-progress) branch on OSX, Linux and FreeBSD, we should use the following instructions

• Retrieve the unstable branch using the command

git clone https:\\git01.codeplex.com\z3 -b unstable

This command will create a new z3 subdirectory with the source code from the unstable branch.
Here are instruction to avoid HTTPS cloning errors: error "RPC failed; result=56, HTTP code = 200" when cloning the Z3 repository

• Create Makefile and build using the commands

cd z3
python scripts/mk_make.py
cd build
make