BZip2 1.0.x CMake

Note: Bzip2 >= 1.1 has its own CMake.

CMake for BZip2 works better than Makefile across compilers and computing platforms.

cmake -B build
cmake --build build

# optional
ctest --test-dir build

cmake --install build

We use CMake FetchContent to retrieve BZip2 1.0.x source from host website, building it unmodified except addition of CMake.