# Returns the host triple.
# Invokes config.guess

function(get_host_triple var)
  if (MSVC)
    if (CMAKE_SIZEOF_VOID_P EQUAL 8)
      set(value "x86_64-pc-windows-msvc")
    else()
      set(value "i686-pc-windows-msvc")
    endif()
  elseif (MINGW AND NOT MSYS)
    if (CMAKE_SIZEOF_VOID_P EQUAL 8)
      set(value "x86_64-w64-windows-gnu")
    else()
      set(value "i686-pc-windows-gnu")
    endif()
  else(MSVC)
    if (CMAKE_HOST_SYSTEM_NAME STREQUAL Windows AND NOT MSYS)
      message(WARNING "unable to determine host target triple")
    else()
      set(config_guess ${LLVM_PATH}/cmake/config.guess)
      execute_process(
        COMMAND sh ${config_guess}
        RESULT_VARIABLE TT_RV
        OUTPUT_VARIABLE TT_OUT
        OUTPUT_STRIP_TRAILING_WHITESPACE
      )
      if (NOT TT_RV EQUAL 0)
        message(FATAL_ERROR "Failed to execute ${config_guess}")
      endif(NOT TT_RV EQUAL 0)
      set(value ${TT_OUT})
    endif()
  endif(MSVC)
  set(${var} ${value} PARENT_SCOPE)
endfunction(get_host_triple var)