ocamlopt writes an error message when the output file contains no dot

[bruno-blanchet]

For instance, the command:

ocamlopt -o cryptoverif str.cmxa parsing_helper.mli parsing_helper.ml occ_map.mli occ_map.ml types.ml ptree.mli parser.mli parser.ml ...

displays:

** Error: Sys_error("cryptoverif: No such file or directory")
File "caml_startup", line 1:
Error: Error during linking

It still generates an executable cryptoverif.exe, which works fine. (So this is not a very serious bug.)
The error message disappears when the command is changed into:

ocamlopt -o cryptoverif.exe str.cmxa parsing_helper.mli parsing_helper.ml occ_map.mli occ_map.ml types.ml ptree.mli parser.mli parser.ml ...

The error happens both with the Installer for 64-bit OCaml 4.02.3 + OPAM and the 32-bit OCaml 4.02.3 + Cygwin32 OPAM.