anchor.diff:      ++ stdenv.lib.optionals enableMySQL [ libmysqlclient zlib ]
       ++ stdenv.lib.optional enableAuthDovecot dovecot
       ++ stdenv.lib.optional enablePAM pam
  -    ++ stdenv.lib.optional enableSPF libspf2;
  +    ++ stdenv.lib.optional enableSPF libspf2
  +    ++ stdenv.lib.optional enableDMARC opendmarc;
   
     preBuild = ''
       sed '
  
positive.code: , enableAuthDovecot ? false, dovecot
  , enablePAM ? false, pam
  , enableSPF ? true, libspf2
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:         s:^# \(SUPPORT_SPF\)=.*:\1=yes:
          s:^# \(LDFLAGS += -lspf2\):\1:
        ''}
        ${stdenv.lib.optionalString enableDMARC ''
          s:^# \(SUPPORT_DMARC\)=.*:\1=yes:
          s:^# \(LDFLAGS += -lopendmarc\):\1:
        ''}
        #/^\s*#.*/d
        #/^\s*$/d
      ' < src/EDITME > Local/Makefile
  