function(verify_architectures file)
  execute_process(
    COMMAND xcrun otool -vf ${RunCMake_TEST_BINARY_DIR}/_install/${file}
    OUTPUT_VARIABLE otool_out
    ERROR_VARIABLE otool_err
    RESULT_VARIABLE otool_result)
  if(NOT otool_result EQUAL "0")
    message(SEND_ERROR "Could not retrieve fat headers: ${otool_err}")
    return()
  endif()

  string(REGEX MATCHALL "architecture [^ \n\t]+" architectures ${otool_out})
  string(REPLACE "architecture " "" actual "${architectures}")
  list(SORT actual)

  set(expected armv7 x86_64)

  if(NOT actual STREQUAL expected)
    message(SEND_ERROR
      "The actual library contains the architectures:\n ${actual} \n"
      "which do not match expected ones:\n ${expected} \n"
      "otool output:\n${otool_out}")
  endif()
endfunction()

verify_architectures(lib/libfoo.dylib)