opam-ci fails on ocigen toolkit when compiling ocsigen-start

[balat]

Every time we do a release of Ocsigen Start, the CI fails to compile Ocsigen Toolkit on a some architectures:

    extras
        arm32-ocaml-5.1
            ocsigen-start.6.3.0 (failed: ocsigen-toolkit.3.3.4 failed to build)
        ppc64-ocaml-5.1
            ocsigen-start.6.3.0 (failed: ocsigen-toolkit.3.3.4 failed to build)
        riscv64-ocaml-4.14
            ocsigen-start.6.3.0 (failed: System package install failed with exit code 100 at command:)
        riscv64-ocaml-5.1
            ocsigen-start.6.3.0 (failed: System package install failed with exit code 100 at command:)
        x86_32-ocaml-4.14
            ocsigen-start.6.3.0 (failed: conf-npm.1 failed to build)
        x86_32-ocaml-5.1
            ocsigen-start.6.3.0 (failed: ocsigen-toolkit.3.3.4 failed to build)

#=== ERROR while compiling ocsigen-toolkit.3.3.4 ==============================#
# context              2.2.0~beta2~dev | linux/arm32 | ocaml-base-compiler.5.1.1 | file:///home/opam/opam-repository
# path                 ~/.opam/5.1/.opam-switch/build/ocsigen-toolkit.3.3.4
# command              ~/.opam/opam-init/hooks/sandbox.sh build make -j79
# exit-code            2
# env-file             ~/.opam/log/ocsigen-toolkit-7-0c2b7e.env
# output-file          ~/.opam/log/ocsigen-toolkit-7-0c2b7e.out
### output ###
# mkdir -p _deps
# mkdir -p _deps/src/widgets/
# mkdir -p _deps/src/widgets/
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_buttons.eliom > _deps/src/widgets/ot_buttons.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_buttons.eliomi > _deps/src/widgets/ot_buttons.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_calendar.eliom > _deps/src/widgets/ot_calendar.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_calendar.eliomi > _deps/src/widgets/ot_calendar.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_carousel.eliom > _deps/src/widgets/ot_carousel.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_carousel.eliomi > _deps/src/widgets/ot_carousel.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_color_picker.eliom > _deps/src/widgets/ot_color_picker.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_color_picker.eliomi > _deps/src/widgets/ot_color_picker.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_drawer.eliom > _deps/src/widgets/ot_drawer.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_drawer.eliomi > _deps/src/widgets/ot_drawer.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_form.eliom > _deps/src/widgets/ot_form.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_form.eliomi > _deps/src/widgets/ot_form.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_icons.eliom > _deps/src/widgets/ot_icons.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_lib.eliom > _deps/src/widgets/ot_lib.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_lib.eliomi > _deps/src/widgets/ot_lib.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_nodeready.eliom > _deps/src/widgets/ot_nodeready.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_nodeready.eliomi > _deps/src/widgets/ot_nodeready.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_noderesize.eliom > _deps/src/widgets/ot_noderesize.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_noderesize.eliomi > _deps/src/widgets/ot_noderesize.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_page_transition.eliom > _deps/src/widgets/ot_page_transition.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_page_transition.eliomi > _deps/src/widgets/ot_page_transition.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_picture_uploader.eliom > _deps/src/widgets/ot_picture_uploader.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_picture_uploader.eliomi > _deps/src/widgets/ot_picture_uploader.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_popup.eliom > _deps/src/widgets/ot_popup.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_popup.eliomi > _deps/src/widgets/ot_popup.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_pulltorefresh.eliom > _deps/src/widgets/ot_pulltorefresh.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_pulltorefresh.eliomi > _deps/src/widgets/ot_pulltorefresh.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_range.eliom > _deps/src/widgets/ot_range.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_range.eliomi > _deps/src/widgets/ot_range.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_size.eliom > _deps/src/widgets/ot_size.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_size.eliomi > _deps/src/widgets/ot_size.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_spinner.eliom > _deps/src/widgets/ot_spinner.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_spinner.eliomi > _deps/src/widgets/ot_spinner.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_sticky.eliom > _deps/src/widgets/ot_sticky.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_sticky.eliomi > _deps/src/widgets/ot_sticky.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_style.eliom > _deps/src/widgets/ot_style.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_style.eliomi > _deps/src/widgets/ot_style.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_swipe.eliom > _deps/src/widgets/ot_swipe.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_swipe.eliomi > _deps/src/widgets/ot_swipe.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_time_picker.eliom > _deps/src/widgets/ot_time_picker.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_time_picker.eliomi > _deps/src/widgets/ot_time_picker.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_tip.eliom > _deps/src/widgets/ot_tip.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_tip.eliomi > _deps/src/widgets/ot_tip.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_toggle.eliom > _deps/src/widgets/ot_toggle.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_toggle.eliomi > _deps/src/widgets/ot_toggle.eliomi.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_tongue.eliom > _deps/src/widgets/ot_tongue.eliom.server
# eliomdep -server -ppx -package calendar -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_tongue.eliomi > _deps/src/widgets/ot_tongue.eliomi.server
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_buttons.eliom > _deps/src/widgets/ot_buttons.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_buttons.eliomi > _deps/src/widgets/ot_buttons.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_calendar.eliom > _deps/src/widgets/ot_calendar.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_calendar.eliomi > _deps/src/widgets/ot_calendar.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_carousel.eliom > _deps/src/widgets/ot_carousel.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_carousel.eliomi > _deps/src/widgets/ot_carousel.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_color_picker.eliom > _deps/src/widgets/ot_color_picker.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_color_picker.eliomi > _deps/src/widgets/ot_color_picker.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_drawer.eliom > _deps/src/widgets/ot_drawer.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_drawer.eliomi > _deps/src/widgets/ot_drawer.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_form.eliom > _deps/src/widgets/ot_form.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_form.eliomi > _deps/src/widgets/ot_form.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_icons.eliom > _deps/src/widgets/ot_icons.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_lib.eliom > _deps/src/widgets/ot_lib.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_lib.eliomi > _deps/src/widgets/ot_lib.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_nodeready.eliom > _deps/src/widgets/ot_nodeready.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_nodeready.eliomi > _deps/src/widgets/ot_nodeready.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_noderesize.eliom > _deps/src/widgets/ot_noderesize.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_noderesize.eliomi > _deps/src/widgets/ot_noderesize.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_page_transition.eliom > _deps/src/widgets/ot_page_transition.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_page_transition.eliomi > _deps/src/widgets/ot_page_transition.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_picture_uploader.eliom > _deps/src/widgets/ot_picture_uploader.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_picture_uploader.eliomi > _deps/src/widgets/ot_picture_uploader.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_popup.eliom > _deps/src/widgets/ot_popup.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_popup.eliomi > _deps/src/widgets/ot_popup.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_pulltorefresh.eliom > _deps/src/widgets/ot_pulltorefresh.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_pulltorefresh.eliomi > _deps/src/widgets/ot_pulltorefresh.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_range.eliom > _deps/src/widgets/ot_range.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_range.eliomi > _deps/src/widgets/ot_range.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_size.eliom > _deps/src/widgets/ot_size.eliom.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_size.eliomi > _deps/src/widgets/ot_size.eliomi.client
# eliomdep -client -ppx -package calendar -package js_of_ocaml -package js_of_ocaml-lwt -package js_of_ocaml-ppx -package lwt_ppx -package js_of_ocaml-ppx_deriving_json -eliom-inc src/widgets/ src/widgets/ot_spinner.eliom > _deps/src/widgets/ot_spinner.eliom.client
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# Makefile:173: .depend: No such file or directory
# make: *** [Makefile:184: _deps/src/widgets/ot_form.eliomi.server] Error 2
# make: *** Waiting for unfinished jobs....
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_buttons.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_nodeready.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_icons.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_calendar.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_noderesize.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_color_picker.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_buttons.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_lib.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_swipe.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_style.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_toggle.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_sticky.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_nodeready.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_size.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_tongue.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_pulltorefresh.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_lib.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_tip.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_carousel.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_form.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_spinner.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_swipe.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_tip.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_drawer.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_drawer.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_style.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_popup.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_spinner.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_range.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_color_picker.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_sticky.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_page_transition.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_time_picker.eliomi.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_noderesize.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_time_picker.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_tongue.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_toggle.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_picture_uploader.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_size.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_picture_uploader.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_popup.eliom.server] Error 2
# make: *** [Makefile:184: _deps/src/widgets/ot_pulltorefresh.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_page_transition.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_range.eliomi.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_calendar.eliom.server] Error 2
# File "_none_", line 1:
# Error: Cannot load js_of_ocaml-ppx_deriving_json: this object file uses
#        unsafe features
# make: *** [Makefile:184: _deps/src/widgets/ot_carousel.eliom.server] Error 2