INCLUDE(EnableWarnings)IF(APPLE)# We cannot simply CHECK_FUNCTION_EXISTS on macOS because# MACOSX_DEPLOYMENT_TARGET may be set to a version in the past# that doesn't have futimens. Instead we need to enable warnings# as errors, then check for the symbol existing in `sys/stat.h`,# then reset warnings as errors.ENABLE_WARNINGS(error)CHECK_SYMBOL_EXISTS(futimens sys/stat.h HAVE_FUTIMENS)DISABLE_WARNINGS(error)ELSE()CHECK_FUNCTION_EXISTS(futimens HAVE_FUTIMENS)ENDIF()