@reeseovine I think this is either because of an update to Gram’s extension logic or it was always an issue and I just never noticed because I forgot that I had programs.nix-ld.enable = true in my system configuration (removing it I get the same error as you are). Try adding that and lmk if it works. I’ll see if I can find a decent workaround that doesn’t need it.
It seems that Gram is still pulling in the wasi-sdk (despite requiring a system toolchain also installed), which it then uses for at least portions of the extension building, and as they’re binaries built for normal Linux the linker path they look for doesn’t exist on NixOS without nix-ld. I probably should’ve caught this sooner sorry. This whole solution is currently pretty janky and hopefully will be less necessary for most users as Gram Extensions the Nix Way develops.