add-one example does not build on Windows

[avdv]

Describe the bug Trying to build the //rts:add-one target in the examples project, it fails with:

ld.lld: error: undefined symbol: add_one_hs

>>> referenced by bazel-out/x64_windows-fastbuild/bin/rts/_objs/add-one/main.o:(main)

clang: error: linker command failed with exit code 1 (use -v to see invocation)

To Reproduce

1. checkout rules_haskell
2. cd examples
3. USE_BAZEL_VERSION=6.x bazelisk build //rts:add-one

Expected behavior This should work fine.

Environment

• OS name + version: Windows 2022 (github actions windows-latest)
• Bazel version: 6.5
• Version of the rules: 1.0

Additional context

This seems to be caused by ghc creating an ar archive instead of just a simple object file:

$ ar x libHSrtsZSadd-one-hs.a
$ file One.o
One.o: current ar archive
$ ar t One.o
ghc_6.o
ghc_5.o

The object file is produced by //rts:add-one-hs and called One.o. This file is then added to a static archive:

external/rules_haskell_ghc_windows_amd64/mingw/bin/ar
qc
bazel-out/x64_windows-fastbuild/bin/rts/libHSrtsZSadd-one-hs.a
bazel-out/x64_windows-fastbuild/bin/rts/_obj/add-one-hs/One.o

Trying to use gcc / GNU ld instead of clang resulted in an error from ld, stating that the libHSrtsZSadd-one-hs.a archive is missing an index and suggested to create one using ranlib.