I've been stuck for a few days on a problem with linking clangd-fuzzer getting OoM killed right at the end of buildPhase 18 hours into the clang build. Even -j1 isn't enough.
I tried useMoldLinker, but that's broken right now (due to something not putting NIX_CFLAGS_LINK under env?).
Then I tried updating the system again, but now useMoldLinker causes eval to overflow the stack.

Has anyone found a reasonable solution to building clang (LLVM 20 and 21) without needing ludicrous amounts of memory?
If push comes to shove I could perhaps suffer a larger swap file...

For reference:

[nixos@nixos:~/system]$ free -h
               total        used        free      shared  buff/cache   available
Mem:           7.7Gi       6.0Gi       105Mi          0B       1.6Gi       1.5Gi
Swap:           15Gi       152Mi        15Gi

(There is high memory usage right now because it's in the middle of retrying clang.)