Log Message:
Do not include x11.buildlink3.mk, not intended to be used this way.
Fix MASTER_SITES.
Put lines in standard order.
Add entry to TODO, that it doesn't build for me with:

-- Looking for C++ include atomic
-- Looking for C++ include atomic - not found
CMake Error at src/CMakeLists.txt:159 (INSTALL):
  install TARGETS given no ARCHIVE DESTINATION for static library target
  "spark".