message: Always vendor cmark
  cmark builds fast and this enables using the cmark_exe pseudo
  executable on systems with cmark installed globally
diff: -if(PKG_CONFIG_FOUND)
  - pkg_check_modules(LIBCMARK libcmark)
  -endif()
  -if(NOT LIBCMARK_FOUND)
  set(CMARK_TESTS
  OFF
  CACHE BOOL "" FORCE)
  @@ -17,4 +13,3 @@ if(NOT LIBCMARK_FOUND)
  set(LIBCMARK_LIBRARIES
  cmark_static
  CACHE INTERNAL "libcmark implementation" FORCE)
  -endif()
  