Build requirement for curses is not documented

CMake Error at /usr/share/cmake-3.10/Modules/FindPackageHandleStandardArgs.cmake:137 (message):
  Could NOT find Curses (missing: CURSES_LIBRARY CURSES_INCLUDE_PATH)
Call Stack (most recent call first):
  /usr/share/cmake-3.10/Modules/FindPackageHandleStandardArgs.cmake:378 (_FPHSA_FAILURE_MESSAGE)
  /usr/share/cmake-3.10/Modules/FindCurses.cmake:245 (FIND_PACKAGE_HANDLE_STANDARD_ARGS)
  lang/CMakeLists.txt:269 (find_package)

README_LINUX.md contains no mention of ‘curse’ anywhere, except the irrelevant --recurse-submodules – hence, it’s an undocumented build requirement.

hjh