enable_language(C)
if(NOT CMAKE_C_BYTE_ORDER MATCHES "^(BIG_ENDIAN|LITTLE_ENDIAN)$")
  if(CMAKE_OSX_ARCHITECTURES MATCHES ";ppc|ppc;")
    return()
  endif()
  message(FATAL_ERROR "CMAKE_C_BYTE_ORDER has unexpected value '${CMAKE_C_BYTE_ORDER}'")
endif()

include(TestBigEndian)
test_big_endian(IS_BIG_ENDIAN)
if(IS_BIG_ENDIAN AND NOT CMAKE_C_BYTE_ORDER STREQUAL "BIG_ENDIAN")
  message(FATAL_ERROR "test_big_endian result does not match ABI result")
endif()

# Test legacy check.
set(byte_order "${CMAKE_C_BYTE_ORDER}")
unset(CMAKE_C_BYTE_ORDER)
include(TestBigEndian)
test_big_endian(IS_BIG)
if(IS_BIG AND NOT byte_order STREQUAL "BIG_ENDIAN")
  message(FATAL_ERROR "test_big_endian result does not match ABI result")
endif()