Fix cross compilation on macOS

default.nix

@@ -1,5 +1,5 @@
 {
-  nixpkgsPath ? <nixpkgs>,
+  nixpkgsPath ? ./nixpkgs.nix,
   system ? builtins.currentSystem,
   overlays ? [],
   crossSystem ? (import <nixpkgs/lib>).systems.examples.musl64,

nixpkgs.nix

@@ -0,0 +1,24 @@
+{ ... }@args:
+import
+  (fetchGit {
+    url = https://github.com/NixOS/nixpkgs;
+    rev = "47b551c6a854a049045455f8ab1b8750e7b00625";
+  })
+  (args // {
+    config.packageOverrides = pkgs: {
+      openssl = (pkgs.openssl.override {
+        # `perl` is only used at build time, but the derivation incorrectly uses host `perl`
+        # as an input.
+        perl = pkgs.buildPackages.buildPackages.perl;
+      }).overrideAttrs (_: {
+        # `man` output is troublesome, disable it.
+        installTargets = "install_sw";
+        outputs = [ "bin" "dev" "out" ];
+      });
+
+      # These packages need rebuilding because of the harmless `openssl` change above.
+      # The test suites for them fails (for some reason) so just disable them.
+      libuv = pkgs.libuv.overrideAttrs (_: { doCheck = false; });
+      e2fsprogs = pkgs.e2fsprogs.overrideAttrs (_: { doCheck = false; });
+    };
+  })

overlay/json2toml.nix

@@ -1,7 +1,7 @@
 { remarshal, runCommand }:
-json:
+{ name, json }:
   runCommand
-    "to.toml"
+    "${name}-to.toml"
     {
       nativeBuildInputs = [remarshal];
       passAsFile = [ "json" ];

overlay/mkcrate.nix

@@ -522,10 +522,11 @@ let
     nativeBuildInputs =
       sort
         (a: b: "${a}" < "${b}")
-        ([ buildPackages.jq cargo buildPackages.pkg-config ] ++
+        ([ cargo buildPackages.pkg-config ] ++
          map accessPackage nativeBuildInputs ++
          accessConfig "nativeBuildInputs" [] package-id ++
          optional (!isNull target.nativeBuildInputs or null) target.nativeBuildInputs or []);
+    depsBuildBuild = [ buildPackages.buildPackages.stdenv.cc buildPackages.buildPackages.jq ];
 
     # Running the default `strip -S` command on Darwin corrupts the
     # .rlib files in "lib/".
@@ -566,7 +567,7 @@ let
       cat > .cargo/config <<'EOF'
       [target."${realHostTriple stdenv.buildPlatform}"]
       linker = "${ccForBuild}"
-    '' + optionalString (stdenv.buildPlatform != stdenv.hostPlatform && !stdenv.hostPlatform.isWasi && isNull target) ''
+    '' + optionalString (stdenv.buildPlatform != stdenv.hostPlatform && !(stdenv.hostPlatform.isWasi or false) && isNull target) ''
       [target."${host-triple}"]
       linker = "${ccForHost}"
     '' + ''
@@ -578,7 +579,7 @@ let
       echo name = \"${name}\" >> Cargo.lock
       echo version = \"${version}\" >> Cargo.lock
       echo source = \"registry+${registry}\" >> Cargo.lock
-      cp ${rustLib.json2toml patched-manifest} Cargo.toml
+      cp ${rustLib.json2toml { inherit name; json = patched-manifest; }} Cargo.toml
     '';
 
     configurePhase =

overlay/real-host-triple.nix

@@ -5,7 +5,7 @@ let
   kernel = platform.parsed.kernel.name;
   abi = platform.parsed.abi.name;
 in
-if platform.isWasi then
+if platform.isWasi or false then
   "${platform.parsed.cpu.name}-wasi"
 else {
   "i686-linux"        = "i686-unknown-linux-${abi}";

overlay/toml2json.nix

@@ -1,8 +1,8 @@
 { lib, remarshal, runCommand }:
-toml:
+{ name, toml }:
 let
   json = runCommand
-    "to.json"
+    "${name}-to.json"
     {
       nativeBuildInputs = [remarshal];
       passAsFile = [ "toml" ];