Those are some building hints how I built the dependencies for the scripting interface. Useful for people who get easily lost and have no idea where to start.
mkdir cling && cd cling
git clone http://root.cern.ch/git/llvm.git src
cd src
git checkout cling-patches
cd tools
git clone http://root.cern.ch/git/cling.git
git clone http://root.cern.ch/git/clang.git
cd clang
git checkout cling-patches
cd ../../..
mkdir build && cd build
cmake \
-DCMAKE_INSTALL_PREFIX=/opt/cling \
-DCMAKE_BUILD_TYPE=Release \
-DLLVM_TARGETS_TO_BUILD=X86 \
-DBUILD_SHARED_LIBS=ON \
-DLLVM_ENABLE_CXX1Y=ON \
-DLLVM_ENABLE_CXX1Z=ON \
-DLLVM_INCLUDE_DOCS=OFF \
-DLLVM_INCLUDE_EXAMPLES=OFF \
-DLLVM_BUILD_EXAMPLES=OFF \
-DLLVM_INCLUDE_TESTS=OFF \
-DLLVM_BUILD_TESTS=OFF \
-DLLVM_INCLUDE_UTILS=OFF \
-DLLVM_BUILD_UTILS=OFF \
../src
make
make install
QAPI-IDE CMake Option: -DCling_DIR=/opt/cling