[openimageio] "/utf-8 is required on Windows" error returns with version v3.0.0.3

[crgnam]

Is your feature request related to a problem? Please describe.

When using Visual Studio 2022, if you include headers from OpenImageIO (such as OpenImageIO/imagebuf.h) you get the following compilation error:

C:<foo>\out\build\x64-Release\vcpkg_installed\x64-windows\include\OpenImageIO\detail\fmt\base.h(458): error C2338: static_assert failed: 'Unicode support requires compiling with /utf-8'

This appears to be related to #41405, which was resolved by #41429. However looking at the portfile, the change (adding -DINTERNALIZE_FMT=OFF to the portfile.cmake) is still present in the most recent port for version v3.0.0.3, so I am unsure how related it is.

I do not get the issue when compiling with g++ (Ubuntu 11.4.0-1ubuntu1~22.04) 11.4.0, which I do using the following commands:

mkdir build;
cd build;
cmake ../ -DCMAKE_BUILD_TYPE=Release -DCMAKE_TOOLCHAIN_FILE=<path/to/my/vcpkg>/scripts/buildsystems/vcpkg.cmake
cmake --build .

Proposed solution

Unsure?

Describe alternatives you've considered

Unsure of alternatives (for time being, I am continuing to use a previous version of OpenImageIO, which works without issue)

Additional context

This public repo contains a minimal working example to reproduce the error.