mtime-windows fails to build with latest ocamlbuild

[hcarty]

If I use the suggested ocamlbuild pin (ocamlbuild's latest master) the mtime-windows build fails for me. Same failure pinning to 0.10.0. However if I pin to https://github.com/ocaml/ocamlbuild.git#90902a0617cee5c95c41e63d012475ce03b04689 explicitly then the build works fine. Seems to be some issue with cmxs creation and the C stubs.

That commit is the one adding -toolchain support to ocamlbuild.

Output from a failed compilation:

$ opam install mtime-windows
The following actions will be performed:
  ∗  install mtime-windows 0.8.3

=-=- Gathering sources =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  🐫

=-=- Processing actions -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  🐫
[ERROR] The compilation of mtime-windows failed at "env OCAMLFIND_TOOLCHAIN=windows ocaml pkg/build.ml native=true native-dynlink=true jsoo=false".
Processing  1/1: [mtime-windows: ocamlfind windows]
#=== ERROR while installing mtime-windows.0.8.3 ===============================#
# opam-version 1.2.2
# os           darwin
# command      env OCAMLFIND_TOOLCHAIN=windows ocaml pkg/build.ml native=true native-dynlink=true jsoo=false
# path         /Users/hcarty/.opam/4.04.0+win64bit-shared+flambda/build/mtime-windows.0.8.3
# compiler     4.04.0
# exit-code    10
# env-file     /Users/hcarty/.opam/4.04.0+win64bit-shared+flambda/build/mtime-windows.0.8.3/mtime-windows-84977-ad8886.env
# stdout-file  /Users/hcarty/.opam/4.04.0+win64bit-shared+flambda/build/mtime-windows.0.8.3/mtime-windows-84977-ad8886.out
# stderr-file  /Users/hcarty/.opam/4.04.0+win64bit-shared+flambda/build/mtime-windows.0.8.3/mtime-windows-84977-ad8886.err
### stdout ###
# [...]
# ocamlfind ocamlopt -c -g -bin-annot -safe-string -I src-os -o src-os/mtime.cmx src-os/mtime.ml
# ocamlfind ocamlopt -a -cclib -lmtime_stubs src-os/mtime_base.cmx src-os/mtime.cmx -o src-os/mtime.cmxa
# ocamlfind ocamlc -c -g -bin-annot -safe-string -I src-os -o src-os/mtime.cmo src-os/mtime.ml
# ocamlfind ocamlc -a -dllib -lmtime_stubs src-os/mtime_base.cmo src-os/mtime.cmo -o src-os/mtime.cma
# ocamlfind ocamlopt -shared -linkall src-os/libmtime_stubs.a src-os/mtime.cmxa -o src-os/mtime.cmxs
# + ocamlfind ocamlopt -shared -linkall src-os/libmtime_stubs.a src-os/mtime.cmxa -o src-os/mtime.cmxs
# ** Fatal error: Cannot find file "libmtime_stubs"
# File "caml_startup", line 1:
# Error: Error during linking
# Command exited with code 2.



=-=- Error report -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=  🐫
The following actions failed
  ∗  install mtime-windows 0.8.3
No changes have been performed

[hcarty]

I can submit a PR updating the README to specify this new pin if you think that's the right approach but I'm not sure if that would cause other issues.

[whitequark]

This seems wrong. What exactly is the issue here?

[hcarty]

I think the flags passed to ocamlopt for the cmxs build are incorrect but I don't know enough about how a cmxs is supposed to be built to know the exact issue. If I get time to look into it more I'll comment here.