llvmPackages_rocm.llvm explore splitting the output

[Artturin]

Issue description

on my system many of the largest include dirs are from rocm packages

6.0M    /nix/store/l1w0j967cmbwwvs1hiwwgkr0zw88jc4y-rocm-llvm-clang-5.4.4/lib/clang/15.0.0/include/
6.1M    /nix/store/ai03g6yimz2rfid2b983nh7ksw5db06q-rocm-llvm-llvm-5.4.4/include/
7.8M    /nix/store/gcf2fgvjxvq59ailnm5lfhwpf5i9q9n2-gcc-12.3.0/lib/gcc/i686-unknown-linux-gnu/12.3.0/plugin/include/
12M     /nix/store/gcf2fgvjxvq59ailnm5lfhwpf5i9q9n2-gcc-12.3.0/include/
14M     /nix/store/jfkg8g29kgnx8im1dpb9hnjxza3gb9jf-qtbase-6.5.1/include/
18M     /nix/store/7yf7slxfqshljr89mcg7ywmj0g4fhldi-clang-14.0.6-lib/lib/clang/14.0.6/include/
18M     /nix/store/bfxhrxlbabg79z85mlyai9favwvjiqgf-qtbase-5.15.9-dev/include/
18M     /nix/store/l1w0j967cmbwwvs1hiwwgkr0zw88jc4y-rocm-llvm-clang-5.4.4/include/
19M     /nix/store/sf2x7k9jxn20dwr5vdch0y3gf42s2g45-llvm-16.0.6-dev/include/
22M     /nix/store/bxrhq6050zdaq5ldvlwhx3045y5dqlfw-rocm-llvm-llvm-5.4.4/include/

Steps to reproduce

nix path-info -r /run/current-system | xargs -i fd --type d --glob 'include' {} 2>/dev/null | xargs du -shc --apparent-size | sort -hk1

[Madouura]

Splitting the output aside from the current split outputs will likely require patching llvm.
bin and dev end up with cyclical references, lib has it's own problems with llvm since things are set manually in the cmake files.
I wonder if we could do what we currently do with bcachefs and linux, and use the rocm llvm repo as a patch to the corresponding version? This way we could use the relevant llvm derivation's split outputs and patches.

[Madouura]

I've been working on splitting outputs for rocm-llvm, but overall it's buggy and frankly not worth the effort to me.
I'm not against someone else working on a proper rocm-llvm split, but it's gonna be very difficult, as I've experienced.