Description of problem:
rust-bindgen-cli is currently using LLVM 15 as a backend even though Fedora 38 and newer use LLVM 16. This breaks compilation of Linux when building with LLVM and spits about this error:

***
*** libclang (used by the Rust bindings generator 'bindgen')
*** version does not match Clang's. This may be a problem.
***   libclang version: 15.0.7
***   Clang version:    16.0.6
***
  RUSTC L rust/core.o
  BINDGEN rust/bindings/bindings_generated.rs
  BINDGEN rust/bindings/bindings_helpers_generated.rs
  BINDGEN rust/uapi/uapi_generated.rs
error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]
panicked at 'Unable to generate bindings: ClangDiagnostic("error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]\n")', main.rs:52:36
make[2]: *** [rust/Makefile:317: rust/uapi/uapi_generated.rs] Error 101
make[2]: *** Deleting file 'rust/uapi/uapi_generated.rs'
make[2]: *** Waiting for unfinished jobs....
error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]
panicked at 'Unable to generate bindings: ClangDiagnostic("error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]\n")', main.rs:52:36
make[2]: *** [rust/Makefile:311: rust/bindings/bindings_generated.rs] Error 101
make[2]: *** Deleting file 'rust/bindings/bindings_generated.rs'
error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]
panicked at 'Unable to generate bindings: ClangDiagnostic("error: unknown warning option '-Wno-cast-function-type-strict'; did you mean '-Wno-cast-function-type'? [-Wunknown-warning-option]\n")', main.rs:52:36
make[2]: *** [rust/Makefile:331: rust/bindings/bindings_helpers_generated.rs] Error 101
make[2]: *** Deleting file 'rust/bindings/bindings_helpers_generated.rs'
warning: unknown feature specified for `-Ctarget-feature`: `fp-armv8`
  |
  = note: it is still passed through to the codegen backend
  = help: consider filing a feature request

warning: 1 warning emitted

make[1]: *** [/builddir/build/BUILD/linux-asahi-wip/Makefile:1287: prepare] Error 2
make: *** [Makefile:234: __sub-make] Error 2

I was able to fix this by using the testing version of the package (0.68.1) since that was built recently and uses LLVM 16 as a backend.

Version-Release number of selected component (if applicable):
0.63.0-4.fc38

How reproducible:
Can always be reproduced.

Steps to Reproduce:
1. Enable CONFIG_RUST in the defconfig.
2. Set "export LLVM=1" to build with LLVM.
3. make

How to fix:
Rebuild the package.