set(f "${CMAKE_CURRENT_BINARY_DIR}/not_a_binary.txt")
file(WRITE "${f}" "Not a binary.\n")
file(RPATH_CHECK FILE "${f}" RPATH "/some/rpath")
if(EXISTS "${f}")
  message(FATAL_ERROR "RPATH_CHECK did not remove\n ${f}\nfor non-empty RPATH")
endif()