message: Some CMake fixes that I found when building OS/X (didn't fail on Linux/Windows
diff: cmake_minimum_required(VERSION 3.13)
  #project(libground VERSION "0.0.0" LANGUAGES CXX)
  +include(FilesystemResolver)
  +
  option(LIBGROUND_TESTING "Enables building of unittests for libground [default: ON]" ON)
  if(MSVC)
  @@ -12,9 +14,12 @@ add_library(ground STATIC
  FileChangeWatcher.cpp FileChangeWatcher.h
  stdfs.h
  )
  -
  target_include_directories(ground PUBLIC ${PROJECT_SOURCE_DIR}/src ${CMAKE_SOURCE_DIR}/src)
  +if(Boost_FILESYSTEM_FOUND)
  + target_link_libraries(ground PRIVATE ${Boost_FILESYSTEM_LIBRARY})
  +endif()
  +
  # ----------------------------------------------------------------------------
  if(LIBGROUND_TESTING)
  enable_testing()
  