Crash when ocamlfind not installed because of duplicate compiler-libs.toplevel META

[nojb]

Internal error, please report upstream including the contents of _build/log.
Description:
  ("Map.add_exn: key already exists", { key = "compiler-libs.toplevel" })
Raised at file "src/stdune/code_error.ml", line 9, characters 30-62
Called from file "map.ml", line 281, characters 18-28
Called from file "map.ml", line 289, characters 21-33
Called from file "map.ml", line 289, characters 21-33
Called from file "src/dune_rules/findlib/findlib.ml", line 461, characters
  8-70
Called from file "list.ml", line 121, characters 24-34
Called from file "src/dune_rules/findlib/findlib.ml", line 474, characters
  6-79
Called from file "src/dune_rules/findlib/findlib.ml", line 538, characters
  28-50
Called from file "src/dune_rules/findlib/findlib.ml", line 570, characters
  14-43
Called from file "src/dune_rules/findlib/findlib.ml", line 576, characters
  11-59
...

Maybe related to #4175?