[clang] [llvm] Define pointer layout for AVR program address space (PR #134254)

[James Wainwright via llvm-commits]

jwnrt wrote:

CC @benshi001

To be 100% honest I haven't tested this on AVR silicon yet. My motivation for the change is to allow for non-zero data address spaces in Rust which parses these LLVM address spaces, but would then use both 64-bit and 16-bit pointers for AVR. Apologies if this is bad practice!

https://github.com/llvm/llvm-project/pull/134254