anchor.diff:    CIFS_XATTR y
     CIFS_POSIX y
     CIFS_FSCACHE y
  +  ${optionalString (versionAtLeast version "3.12") ''
  +    CEPH_FSCACHE y
  +  ''}
  +  ${optionalString (versionAtLeast version "3.14") ''
  +    CEPH_FS_POSIX_ACL y
  +  ''}
   
     # Security related features.
     STRICT_DEVMEM y # Filter access to /dev/mem
  
positive.code:   IP_DCCP_CCID3 n # experimental
    CLS_U32_PERF y
    CLS_U32_MARK y
  
    # Wireless networking.
    CFG80211_WEXT? y # Without it, ipw2200 drivers don't build
  
negative.code:   ${optionalString (!stdenv.is64bit) ''
      HIGHMEM64G? y # We need 64 GB (PAE) support for Xen guest support.
    ''}
    INTEL_IOMMU_DEFAULT_ON y
    ${optionalString (versionAtLeast version "3.9") ''
      VFIO_PCI_VGA y
    ''}
    VIRT_DRIVERS y
  
    # Media support.
    ${optionalString (versionAtLeast version "3.6") ''
  