Makefile highlighting, be sure $N2, $(N)2, $$N2 look different

[Dan Jacobson]

Here the $N's (equivalent to $(N)'s) should be highlighted,
else they seem like simple $$N2's.
$ cat Makefile
looseL.$g:zhiIIpnt.csv
        $R $S "SELECT MakeLine($N1.geometry, $N2.geometry) AS geom$(\
        )FROM $N1 INNER JOIN $N2 ON $N1.fid = $N2.fid"