anchor.diff:      ++ lib.optional enableAuthDovecot dovecot
       ++ lib.optional enablePAM pam
       ++ lib.optional enableSPF libspf2
  -    ++ lib.optional enableDMARC opendmarc;
  +    ++ lib.optional enableDMARC opendmarc
  +    ++ lib.optional enableRedis hiredis;
   
     preBuild = ''
       sed '
  
positive.code: , enablePAM ? false, pam
  , enableSPF ? true, libspf2
  , enableDMARC ? true, opendmarc
  }:
  
  stdenv.mkDerivation rec {
  
negative.code:         s:^# \(SUPPORT_DMARC\)=.*:\1=yes:
          s:^# \(LDFLAGS += -lopendmarc\):\1:
        ''}
        ${lib.optionalString enableRedis ''
          s:^# \(LOOKUP_REDIS=yes\)$:\1:
          s:^\(LOOKUP_LIBS\)=\(.*\):\1=\2 -lhiredis -L${hiredis}/lib/hiredis:
          s:^# \(LOOKUP_LIBS\)=.*:\1=-lhiredis -L${hiredis}/lib/hiredis:
          s:^\(LOOKUP_INCLUDE\)=\(.*\):\1=\2 -I${hiredis}/include/hiredis/:
          s:^# \(LOOKUP_INCLUDE\)=.*:\1=-I${hiredis}/include/hiredis/:
        ''}
        #/^\s*#.*/d
        #/^\s*$/d
      ' < src/EDITME > Local/Makefile
  