Cast a macro argument to int to fix a C++20 error.

[Cons-Cat]

C++ 20 errors for me on several expansions of the KHR_DFDSETVAL macro because it attempts to bitwise-and two different types of enums. For example:

/home/conscat/vulkan-experiments/KTX-Software/lib/basis_encode.cpp:256:5: error: invalid bitwise operation between different enumeration types ('_khr_df_vendorid_e' and '_khr_df_mask_e')
  256 |     KHR_DFDSETVAL(nbdb, VENDORID, KHR_DF_VENDORID_KHRONOS);
      |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/home/conscat/vulkan-experiments/KTX-Software/include/KHR/khr_df.h:109:13: note: expanded from macro 'KHR_DFDSETVAL'
  109 |     (((val) & (KHR_DF_MASK_ ## X)) << (KHR_DF_SHIFT_ ## X)))
      |       ~~~~~ ^ ~~~~~~~~~~~~~~~~~~~

This PR simply casts the value to an int inside of the macro.

[CLAassistant]

All committers have signed the CLA.

[MarkCallow]

CI passed a few days ago using clang 20.0.0git (https:/github.com/llvm/llvm-project d6344c1cd0d099f8d99ee320f33fc9254dbe8288. Are you using a newer version than this, @Cons-Cat.

[Cons-Cat]

My version was 2 weeks old.

[Cons-Cat]

The issue was not due to my version of Clang, it was due to my CMAKE_CXX_FLAGS containing -std=gnu++26. Apparently C++20 deprecated implicit enum conversions in this context. Arguably I shouldn't have had that flag there, but this is the only error I have that prevents building the library this way.

[MarkCallow]

@Cons-Cat Thank you for clearing up the confusion of c++20 vs clang v20.

I am looking into the reuse failure. It clearly has nothing to do with the change you have made. I just tried the latest reuse locally and it passes so I don't have any idea of the cause at present. Please confirm your branch contains the file REUSE.toml.

[MarkCallow]

I re-ran the reuse job and it passed. I have no idea what caused an apparently temporary issue before.