Boost not listed in README dependencies but required by cmake

[ssokolow]

When running the cmake .. step on a recently reinstalled Kubuntu 20.04 LTS system, I encountered this error message:

CMake Error at /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:146 (message):
  Could NOT find Boost (missing: Boost_INCLUDE_DIR filesystem system)
Call Stack (most recent call first):
  /usr/share/cmake-3.16/Modules/FindPackageHandleStandardArgs.cmake:393 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.16/Modules/FindBoost.cmake:2179 (find_package_handle_standard_args)
  src/CMakeLists.txt:16 (find_package)

Boost isn't in the list of dependencies in the README so one of them is wrong.

(sudo apt-get install libboost-filesystem-dev libboost-system-dev got me past it.)