anchor.diff:    FHANDLE y # used by systemd
     FRONTSWAP y
     FUSION y # Fusion MPT device support
  -  IDE_GD_ATAPI y # ATAPI floppy support
  +  IDE n # deprecated IDE support
     ${optionalString (versionAtLeast version "4.3") ''
       IDLE_PAGE_TRACKING y
     ''}
  
positive.code:   ${optionalString (versionOlder version "4.4") ''
      B43_PCMCIA? y
    ''}
    BLK_DEV_CMD640_ENHANCED y # CMD640 enhanced support
    BLK_DEV_IDEACPI y # IDE ACPI support
    BLK_DEV_INTEGRITY y
    BSD_PROCESS_ACCT_V3 y
    BT_HCIUART_BCSP? y
  
negative.code:     `versionAtLeast`.
  
    Then do test your change by building all the kernels (or at least
    their configs) in Nixpkgs or else you will guarantee lots and lots
    of pain to users trying to switch to an older kernel because of some
    hardware problems with a new one.
  
  