With an Ubuntu single-user install of nix, and updated via nix-channel --update; nix-env --install --attr nixpkgs.nix nixpkgs.cacert

nix (Nix) 2.18.1

Running the command from the Ladybird build docs:

nix --extra-experimental-features nix-command --extra-experimental-features flakes -- develop ./Toolchain#ladybird

and then trying to build ladybird via serenity.sh

./Meta/serenity.sh run lagom ladybird

Gives a bunch of errors about finding libstdc++

[1/2317] Generating Userland/Services/RequestServer/RequestClientEndpoint.h
FAILED: Userland/Services/RequestServer/RequestClientEndpoint.h /home/andrew/serenity/Build/lagom/Userland/Services/RequestServer/RequestClientEndpoint.h 
cd /home/andrew/serenity/Build/lagom && /home/andrew/serenity/Build/lagom/bin/IPCCompiler /home/andrew/serenity/Userland/Services/RequestServer/RequestClient.ipc -o Userland/Services/RequestServer/RequestClientEndpoint.h.tmp && /nix/store/vnhl4zdy7igx9gd3q1d548vwzz15a9ma-cmake-3.27.7/bin/cmake -E copy_if_different Userland/Services/RequestServer/RequestClientEndpoint.h.tmp Userland/Services/RequestServer/RequestClientEndpoint.h && /nix/store/vnhl4zdy7igx9gd3q1d548vwzz15a9ma-cmake-3.27.7/bin/cmake -E remove Userland/Services/RequestServer/RequestClientEndpoint.h.tmp
/home/andrew/serenity/Build/lagom/bin/IPCCompiler: error while loading shared libraries: libstdc++.so.6: cannot open shared object file: No such file or directory
[2/2317] Generating Userland/Services/RequestServer/RequestServerEndpoint.h
FAILED: Userland/Services/RequestServer/RequestServerEndpoint.h /home/andrew/serenity/Build/lagom/Userland/Services/RequestServer/RequestServerEndpoint.h 
cd /home/andrew/serenity/Build/lagom && /home/andrew/serenity/Build/lagom/bin/IPCCompiler /home/andrew/serenity/Userland/Services/RequestServer/RequestServer.ipc -o Userland/Services/RequestServer/RequestServerEndpoint.h.tmp && /nix/store/vnhl4zdy7igx9gd3q1d548vwzz15a9ma-cmake-3.27.7/bin/cmake -E copy_if_different Userland/Services/RequestServer/RequestServerEndpoint.h.tmp Userland/Services/RequestServer/RequestServerEndpoint.h && /nix/store/vnhl4zdy7igx9gd3q1d548vwzz15a9ma-cmake-3.27.7/bin/cmake -E remove Userland/Services/RequestServer/RequestServerEndpoint.h.tmp
/home/andrew/serenity/Build/lagom/bin/IPCCompiler: error while loading shared libraries: libstdc++.so.6: cannot open shared object file: No such file or directory
[3/2317] Generating Userland/Services/WebSocket/WebSocketClientEndpoint.h

Looking at the RPATH of the created binaries:

~/serenity$ readelf -d Build/lagom/bin/IPCCompiler | grep RUNPATH
 0x000000000000001d (RUNPATH)            Library runpath: [$ORIGIN:$ORIGIN/../lib:/home/andrew/serenity/outputs/out/lib]

vs one created by g++ manually

~/serenity$ readelf -d a.out | grep RUNPATH
 0x000000000000001d (RUNPATH)            Library runpath: [/home/andrew/serenity/Toolchain/outputs/out/lib:/nix/store/qn3ggz5sf3hkjs2c797xf7nan3amdxmp-glibc-2.38-27/lib:/nix/store/1z0lkblksl7niy2w5rfv265hw0fn9p1q-gcc-13.2.0-lib/lib]

We are missing the glibc and gcc paths.

So two questions:

• What on earth is Toolchain/outputs/out/lib? Can we tell the nix derivation that native libs will be put in Build/lagom/lib?
• Why don't our built binaries have the correct RUNPATH?

The same errors occur with the serenity flake

cc @networkException