ocaml-openflow- odd (oasis?) error

[Richard Mortier <Richard.Mortier@xxxxxxxxxxxxxxxx>]

get this when building ocaml-openflow:

E: Failure("No one of expected built files '_build/lib/openflow.cmi' exists")

the _oasis etc all mirror ocaml-dns afaics. but using classic-display, i see 
that ocaml-dns runs

...
ocamlfind ocamlopt -c -g -annot -I lib -package re.str -package re -package 
lwt.unix -package lwt.syntax -package lwt -package cstruct.syntax -package 
cstruct -package cryptokit -syntax camlp4o -for-pack Dns -I lib -o lib/zone.cmx 
lib/zone.ml
touch lib/dns.mli  ; if  ocamlfind ocamlopt -pack -g -I lib lib/base64.cmx 
lib/hashcons.cmx lib/operators.cmx lib/name.cmx lib/RR.cmx lib/trie.cmx 
lib/loader.cmx lib/packet.cmx lib/query.cmx lib/zone_parser.cmx 
lib/zone_lexer.cmx lib/zone.cmx -o lib/dns.cmx  ; then  rm -f lib/dns.mli  ; 
else  rm -f lib/dns.mli  ; exit 1; fi
ocamlfind ocamlopt -a -package lwt.syntax lib/dns.cmx -o lib/dns.cmxa


...so what is it that causes the "touch" invocation, why is it required, and 
how do i get it into ocaml-openflow?!

-- 
Cheers,

R.




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