Hi Dmitry,
There is a bug in Meson: '/OPT:REF' must be prefixed with '-Wl,' when using Clang with link.exe, because Clang does not recognize '/OPT:REF' as an argument to pass to linker, but treats it as a filename instead. A patch is not under review: https://github.com/mesonbuild/meson/pull/6483
Thanks for the suggestion. I applied the patch to meson and the OPT error is gone and it now compiles.
Thanks! -- Jeremy Plsek UNH InterOperability Laboratory