This is googleable:
> = note: ld: library not found for -liconv
> clang-16: error: linker command failed with exit code 1 (use -v to see invocation)
But trying to add liconv to buildInputs which is the most common answer and the most common code example does not work.

I have attempted a manual nixpkgs import with crossSystem, and this:

embeddedPackagesFor = {
        aarch64-darwin = let
          pkgs = pkgsFor.aarch64-darwin;
          cross = pkgs.pkgsCross.aarch64-multiplatform;
          rustPlatform = cross.makeRustPlatform {
            inherit (cross) rustc cargo;
            stdenv = cross.clangStdenv;
            # stdenv = lib.pipe cross.stdenv
            #   (with cross.stdenvAdapters; [ makeStatic useMoldLinker ]);
          };
        in {
          aarch64-linux-cell-management-system =
            cross.callPackage ./nix/cell_management_system.nix {
              sourceRoot = ./embedded;
              # inherit rustPlatform;
            };
        };
        x86_64-linux = let
          pkgs = pkgsFor.x86_64-linux;
          cross = pkgs.pkgsCross.aarch64-multiplatform.pkgsStatic;
        in {
          aarch64-linux-cell-management-system =
            cross.callPackage ./nix/cell_management_system.nix {
              sourceRoot = ./embedded;
            };
        };
      };

Am I constructing the environment incorrectly?

This is googleable:
> = note: ld: library not found for -liconv
> clang-16: error: linker command failed with exit code 1 (use -v to see invocation)
But trying to add liconv to buildInputs which is the most common answer and the most common code example does not work.

I have attempted a manual nixpkgs import with crossSystem, and this:

embeddedPackagesFor = {
        aarch64-darwin = let
          pkgs = pkgsFor.aarch64-darwin;
          cross = pkgs.pkgsCross.aarch64-multiplatform;
          rustPlatform = cross.makeRustPlatform {
            inherit (cross) rustc cargo;
            stdenv = cross.clangStdenv;
            # stdenv = lib.pipe cross.stdenv
            #   (with cross.stdenvAdapters; [ makeStatic useMoldLinker ]);
          };
        in {
          aarch64-linux-cell-management-system =
            cross.callPackage ./nix/cell_management_system.nix {
              sourceRoot = ./embedded;
              # inherit rustPlatform;
            };
        };
        x86_64-linux = let
          pkgs = pkgsFor.x86_64-linux;
          cross = pkgs.pkgsCross.aarch64-multiplatform.pkgsStatic;
        in {
          aarch64-linux-cell-management-system =
            cross.callPackage ./nix/cell_management_system.nix {
              sourceRoot = ./embedded;
            };
        };
      };

Am I constructing the environment incorrectly?

Anyone know what the typical pitfalls are with qt cross compiling, what could be causing this issue?

nix build --impure --expr '(import ./. { localSystem.system = "aarch64-linux"; crossSystem.system = "x86_64-linux"; }).renderdoc' gives:

error: builder for '/nix/store/byl5sd3dcj64vlpq9arwya0nhimqpa0b-qtx11extras-5.15.15.drv' failed with exit code 1;
       last 3 log lines:
       > Error: detected mismatched Qt dependencies:
       >     /nix/store/ismcya95ymkr9f1qb6z7nr80njplrxnx-qtbase-5.15.15-dev
       >     /nix/store/3nwrdzbr1kalfad8xvxriapk5l27972m-qtbase-5.15.15-dev

In reply to @kuruczgy:matrix.org

Anyone know what the typical pitfalls are with qt cross compiling, what could be causing this issue?

nix build --impure --expr '(import ./. { localSystem.system = "aarch64-linux"; crossSystem.system = "x86_64-linux"; }).renderdoc' gives:

error: builder for '/nix/store/byl5sd3dcj64vlpq9arwya0nhimqpa0b-qtx11extras-5.15.15.drv' failed with exit code 1;
       last 3 log lines:
       > Error: detected mismatched Qt dependencies:
       >     /nix/store/ismcya95ymkr9f1qb6z7nr80njplrxnx-qtbase-5.15.15-dev
       >     /nix/store/3nwrdzbr1kalfad8xvxriapk5l27972m-qtbase-5.15.15-dev

Hi All. Not sure if this is a good place to ask but I would imagine this group has spent a bit more time groking the details of the host -> target dependency theory from the nixpkgs manual. Is this correct?

let mapOffset(h, t, i) = i + (if i <= 0 then h else t - 1)

dep(h0, t0, A, B)
propagated-dep(h1, t1, B, C)
h0 + h1 in {-1, 0, 1}
h0 + t1 in {-1, 0, -1}
----------------------------- Take immediate dependencies' propagated dependencies
propagated-dep(mapOffset(h0, t0, h1),
               mapOffset(h0, t0, t1),
               A, C)

shouldn't the final line be just dep instead of propagated-dep ?
because otherwise I think a propagatedBuildInputs would be propagated across a whole buildInputs chain.
eg if propagated-dep(0, 1, C, D), dep(0, 1, B, C), dep(0, 1, A, B) then this results in propagated-dep(0, 1, B, D), propagated-dep(0, 1, A, D)