2.4.6: fails to compile on OSX with ocaml 4.02.1

[avsm]

findlib: [WARNING] Interface topdirs.cmi occurs in several directories: /Users/avsm/.opam/4.02.1/lib/ocaml, /Users/avsm/.opam/4.02.1/lib/ocaml/compiler-libs
/Users/avsm/.opam/4.02.1/bin/ocamlfind ocamlc -a -o ppx/ppx.cma
/Users/avsm/.opam/4.02.1/bin/ocamlfind ocamlopt -a -o ppx/ppx.cmxa
+ /Users/avsm/.opam/4.02.1/bin/ocamlfind ocamlopt -a -o ppx/ppx.cmxa
ar: no archive members specified
usage:  ar -d [-TLsv] archive file ...
    ar -m [-TLsv] archive file ...
    ar -m [-abiTLsv] position archive file ...
    ar -p [-TLsv] archive [file ...]
    ar -q [-cTLsv] archive file ...
    ar -r [-cuTLsv] archive file ...
    ar -r [-abciuTLsv] position archive file ...
    ar -t [-TLsv] archive [file ...]
    ar -x [-ouTLsv] archive [file ...]
File "_none_", line 1:
Error: Error while creating the library ppx/ppx.a
Command exited with code 2.

Empty ar not allowed on OSX

[vouillon]

Indeed, the "ppx" library is empty: no ml mile, and an empty mli file (except for documentation).

I'm not sure how to fix that. Maybe by remove this library and moving Ppx_lwt to the executable "ppx_lwt"?

@Drup and @whitequark, what do you think?

[Drup]

This was the first sane way I could think of to generate documentation for ppx, if anyone has a better idea ....

[whitequark]

Yes, we should definitely get rid of the empty library and properly append the META description using some other way. I have no idea what to do about documentation though. What about adding (*OASIS_START*)(*OASIS_STOP*) to some .odocl file it presumably generates?

(Insert a rant about inflexibility of OASIS)

[whitequark]

Actually I think we could export the ppx rewriter itself as a library. This could be useful in construction of ppx drivers. This way, the corresponding .mli will get documented automatically.

[avsm]

Any progress on fixing this on OSX? We have a dependency on trunk Lwt for the https://github.com/mirage/mirage-profile library, and this keeps coming up. The short term fix would just be to add a dummy ML file to the library to satisfy ar.

[whitequark]

See also ocaml-ppx/ppx_getenv#1 (comment)