anchor.diff:      ++ lib.optional withImageMagick "--with-imagemagick"
       ++ lib.optional withPgtk "--with-pgtk"
       ++ lib.optional withXinput2 "--with-xinput2"
  +    ++ lib.optional (!withToolkitScrollBars) "--without-toolkit-scroll-bars"
     ;
   
     installTargets = [ "tags" "install" ];
  
positive.code: , srcRepo ? false, autoreconfHook ? null, texinfo ? null
  , siteStart ? ./site-start.el
  , nativeComp ? false
  , withPgtk ? false
  , withXinput2 ? false
  , withImageMagick ? lib.versionOlder version "27" && (withX || withNS)
  
negative.code:   if withGTK2 then "gtk2"
    else if withGTK3 then "gtk3"
    else if withMotif then "motif"
    else if withAthena then "athena"
    else "lucid")
  }:
  
  