Destination can be set through the CMAKE_INSTALL_PREFIX variable when
running cmake (for example, `-DCMAKE_INSTALL_PREFIX=/usr/local`).

Files are installed as described below:
  - `build/src/bpftrace` -> `${CMAKE_INSTALL_PREFIX}/sbin`
  - `tools/*` -> `${CMAKE_INSTALL_PREFIX}/share/bpftrace/tools`
  - `man/*` -> `${CMAKE_INSTALL_PREFIX}/man`