$ opam switch create 4.14.2-flambda --packages=ocaml-variants.4.14.2+options,ocaml-option-flambda

<><> Installing new switch packages <><><><><><><><><><><><><><><><><><><><><><>
Switch invariant: ["ocaml-variants" {= "4.14.2+options"} "ocaml-option-flambda"]

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
⬇ retrieved ocaml-config.2  (cached)
∗ installed base-bigarray.base
∗ installed base-threads.base
∗ installed base-unix.base
∗ installed ocaml-option-flambda.1
⬇ retrieved ocaml-variants.4.14.2+options  (cached)
∗ installed ocaml-variants.4.14.2+options
∗ installed ocaml-config.2
∗ installed ocaml.4.14.2
Done.
# To update the current shell environment, run: eval $(opam env --switch=4.14.2-flambda)
$ eval $(opam env --switch=4.14.2-flambda)
$ opam install uunf
The following actions will be performed:
=== install 4 packages
  ∗ ocamlbuild 0.16.1 [required by uunf]
  ∗ ocamlfind  1.9.8  [required by uunf]
  ∗ topkg      1.0.8  [required by uunf]
  ∗ uunf       16.0.0

Proceed with ∗ 4 installations? [Y/n] y

<><> Processing actions <><><><><><><><><><><><><><><><><><><><><><><><><><><><>
⬇ retrieved ocamlbuild.0.16.1  (cached)
⬇ retrieved ocamlfind.1.9.8  (cached)
⬇ retrieved topkg.1.0.8  (cached)
⬇ retrieved uunf.16.0.0  (https://opam.ocaml.org/cache)
∗ installed ocamlfind.1.9.8
∗ installed ocamlbuild.0.16.1
∗ installed topkg.1.0.8
[ERROR] The compilation of uunf.16.0.0 failed at "ocaml pkg/pkg.ml build --dev-pkg false --with-uutf false --with-cmdliner false".

#=== ERROR while compiling uunf.16.0.0 ========================================#
# context     2.4.0 | linux/x86_64 | ocaml-option-flambda.1 ocaml-variants.4.14.2+options | https://opam.ocaml.org#463280143ff4bd61ce0e19b9f77fa4750e7c79f7
# path        ~/.opam/4.14.2-flambda/.opam-switch/build/uunf.16.0.0
# command     ~/.opam/opam-init/hooks/sandbox.sh build ocaml pkg/pkg.ml build --dev-pkg false --with-uutf false --with-cmdliner false
# exit-code   1
# env-file    ~/.opam/log/uunf-1681345-745801.env
# output-file ~/.opam/log/uunf-1681345-745801.out
### output ###
# [...]
# + ocamlfind ocamlc -c -g -bin-annot -safe-string -I src -I support -I test -o src/uunf.cmi src/uunf.mli
# + ocamlfind ocamlopt -c -g -bin-annot -safe-string -I src -I support -I test -o src/uunf_data.cmx src/uunf_data.ml
# + ocamlfind ocamlopt -c -g -bin-annot -safe-string -I src -I support -I test -o src/uunf_data.cmx src/uunf_data.ml
# Fatal error: exception Stack overflow
# Command exited with code 2.
# pkg.ml: [ERROR] cmd ['ocamlbuild' '-use-ocamlfind' '-classic-display' '-j' '4' '-tag' 'debug'
#      '-build-dir' '_build' 'opam' 'pkg/META' 'CHANGES.md' 'LICENSE.md'
#      'README.md' 'src/uunf.a' 'src/uunf.cmxs' 'src/uunf.cmxa' 'src/uunf.cma'
#      'src/uunf_string.cmx' 'src/uunf_string.cmi' 'src/uunf_string.mli'
#      'src/uunf.cmx' 'src/uunf.cmi' 'src/uunf.mli' 'src/uunf_data.cmx'
#      'src/uunf_tmapbyte.cmx' 'src/uunf_tmapbool.cmx' 'src/uunf_tmap.cmx'
#      'src/uunf_fmt.cmx' 'doc/index.mld' 'test/examples.ml']: exited with 10



<><> Error report <><><><><><><><><><><><><><><><><><><><><><><><><><><><><><><>
┌─ The following actions failed
│ λ build uunf 16.0.0
└─ 
┌─ The following changes have been performed
│ ∗ install ocamlbuild 0.16.1
│ ∗ install ocamlfind  1.9.8
│ ∗ install topkg      1.0.8
└─ 

The former state can be restored with:
    /usr/local/bin/opam switch import "/home/simmo/.opam/4.14.2-flambda/.opam-switch/backup/state-20250724115448.export"