camlp4 removal

[Thomas Klausner <wiz%NetBSD.org@localhost>]

Hi!

camlp4 does not support current ocaml versions, and has been marked
BROKEN in pkgsrc since January 2020.

This means we also could not build:

databases/ocaml-macaque
devel/monotone-viz
devel/ocaml-deriving-ocsigen
devel/ocaml-lwt_camlp4
devel/ocaml-optcomp
devel/ocaml-type_conv
devel/verifast
lang/camlp4
net/mldonkey
and thus net/mldonkey-gui
security/sks
textproc/pxp
and thus textproc/harmony
time/wyrd
www/ocaml-http

for nearly 1,5 years now.

I intend to remove camlp4 and these packages after the next branch.

If you're interested in any of these, please check their upstreams to
find out if there's a version that doesn't depend on camlp4, and
update the package.

Thanks,
 Thomas