cd /path/to/sundials
tar xvf sundials-6.3.0.tar.gz cd sundials-6.3.0
mkdir build cd build
export CC=clang CXX=clang++ FC=flang cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/sundials -DEXAMPLES_INSTALL_PATH=/path/to/sundials/examples
make -j make install