deskutils/wyrd: unbreak build after r385012 (camlp4)

ocamlopt.opt -c -pp camlp4o -g -I ./curses install.ml
sh: camlp4o: not found
File "install.ml", line 1:
Error: Error while running external preprocessor

PR: 199847
Reported by: pkg-fallout, maintainer
Submitted by: h.skuhra@gmail.com (maintainer)