anchor.diff:    postInstall =
       ''
         notSupported() {
  -        echo -e "#\!/bin/sh\necho '`basename $1` not supported, $2'\nexit 1" > "$1"
  -        chmod +x $1
  +        unlink $1 || true
         }
   
         # Install git-subtree.
  
positive.code:         wrapProgram $out/libexec/git-core/git-send-email \
                       --set GITPERLLIB "$gitperllib" ''
         else '' # replace git-send-email by notification script
          notSupported $out/libexec/git-core/git-send-email "reinstall with config git = { sendEmailSupport = true } set"
         '')
  
     + stdenv.lib.optionalString withManual ''# Install man pages and Info manual
  
negative.code:      '' else ''
         # Don't wrap Tcl/Tk, replace them by notification scripts
         for prog in bin/gitk libexec/git-core/git-gui; do
           notSupported "$out/$prog"
         done
       '');
  
  