chore(third_party/crate2nix): apply patches to fix cross

Together with temporarily pointing nixpkgs past
b10994c38c61038970a19fa60bfbec21a61755cc, this now fixes cross-
compilation for tvix.

This incorporates the changes proposed in https://cl.tvl.fyi/9888 and
https://cl.tvl.fyi/9889, but by fixing it in crate2nix, and using the
(re-)generated version of it.

Changes were sent upstream at
nix-community/crate2nix#309,
this pulls in a minimal patch for now.

Change-Id: I70bb6f003bbc3e89de9c4eb4985ea4708ac3a9fd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/9890
Autosubmit: flokli <[email protected]>
Reviewed-by: raitobezarius <[email protected]>
Tested-by: BuildkiteCI

Cargo.nix

@@ -11413,7 +11413,7 @@ rec {
             # recreate a file hierarchy as when running tests with cargo
 
             # the source for test data
-            ${pkgs.xorg.lndir}/bin/lndir ${crate.src}
+            ${pkgs.buildPackages.xorg.lndir}/bin/lndir ${crate.src}
 
             # build outputs
             testRoot=target/debug
@@ -11443,10 +11443,12 @@ rec {
           passthru = (crate.passthru or { }) // {
             inherit test;
           };
-        } ''
-        echo tested by ${test}
-        ${lib.concatMapStringsSep "\n" (output: "ln -s ${crate.${output}} ${"$"}${output}") crate.outputs}
-      '';
+        }
+        (lib.optionalString (stdenv.buildPlatform.canExecute stdenv.hostPlatform) ''
+          echo tested by ${test}
+        '' + ''
+          ${lib.concatMapStringsSep "\n" (output: "ln -s ${crate.${output}} ${"$"}${output}") crate.outputs}
+        '');
 
     /* A restricted overridable version of builtRustCratesWithFeatures. */
     buildRustCrateWithFeatures =