[ocaml5-issue] configure flexlink test regression under Cygwin

[jmid]

The merge to main of #438 failed to configure trunk under Cygwin: https://github.com/ocaml-multicore/multicoretests/actions/runs/8156987466/job/22295610153

#=== ERROR while compiling ocaml-variants.5.3.0+trunk+win =====================#
# context              2.0.7 | cygwin/x86_64 |  | git+https://github.com/shym/custom-opam-repository.git
# path                 /cygdrive/d/opam/default/.opam-switch/build/ocaml-variants.5.3.0+trunk+win
# command              /cygdrive/d/opam/default/.opam-switch/build/ocaml-variants.5.3.0+trunk+win/./configure -C --prefix=/cygdrive/d/opam/default --docdir=/cygdrive/d/opam/default/doc/ocaml --disable-warn-error --enable-native-compiler --enable-imprecise-c99-float-ops
# exit-code            1
# env-file             /cygdrive/d/opam/log/ocaml-variants-715-865888.env
# output-file          /cygdrive/d/opam/log/ocaml-variants-715-865888.out
### output ###
# [...]
# checking if libtool supports shared libraries... yes
# checking whether to build shared libraries... yes
# checking whether to build static libraries... yes
# checking how to run the C preprocessor... gcc -E
# checking C compiler vendor... gcc-11-4
# checking whether host executables can be run in the build... yes
# checking whether #! works in shell scripts... yes
# checking whether C compiler accepts -Wold-style-declaration... yes
# checking for flexdll sources... no
# checking for flexlink... flexlink
# checking whether flexlink works... yes
# configure: error: flexlink is not executable from a native Win32 process

This is a regression caused by https://github.com/ocaml/ocaml/pull/12992 and fixed in https://github.com/ocaml/ocaml/pull/13009

[jmid]

Closing as this is now fixed