This NPB uses CMake to build the binary.
You can change what to build in CMakeLists.txt by simply modifying the TARGET_CLASSES and TARGET_BENCHMARKS.
Example of building a regular NPB suite:
mkdir cbuild && cd cbuild
cmake ..
cmake --build .
You can also build each benchmark individually. One example:
mkdir BT/cbuild && cd BT/cbuild
export CLASSES="A B"
cmake ..
cmake --build .
All built binaries will be under cbuild/bin.