k3s: fix build for aarch64

The upstream project already builds and releases for aarch64. This makes
the couple small tweaks that I found necessary for k3s to cross-compile
for aarch64.

I also ran it through nixpkgs-fmt.

pkgs/applications/networking/cluster/k3s/default.nix

@@ -1,6 +1,22 @@
-{ stdenv, lib, makeWrapper, socat, iptables, iproute, bridge-utils
+{ stdenv
-, conntrack-tools, buildGoPackage, git, runc, libseccomp, pkgconfig
+, lib
-, ethtool, utillinux, ipset, fetchFromGitHub, fetchurl, fetchzip
+, makeWrapper
+, socat
+, iptables
+, iproute
+, bridge-utils
+, conntrack-tools
+, buildGoPackage
+, git
+, runc
+, libseccomp
+, pkgconfig
+, ethtool
+, utillinux
+, ipset
+, fetchFromGitHub
+, fetchurl
+, fetchzip
 , fetchgit
 }:
 
@@ -153,6 +169,12 @@ let
     nativeBuildInputs = [ git pkgconfig ];
     buildInputs = [ k3sBuildStage1 k3sPlugins runc ];
 
+    # k3s appends a suffix to the final distribution binary for some arches
+    archSuffix =
+      if stdenv.hostPlatform.system == "x86_64-linux" then ""
+      else if stdenv.hostPlatform.system == "aarch64-linux" then "-arm64"
+      else throw "k3s isn't being built for ${stdenv.hostPlatform.system} yet.";
+
     # In order to build the thick k3s binary (which is what
     # ./scripts/package-cli does), we need to get all the binaries that script
     # expects in place.
@@ -182,7 +204,7 @@ let
       pushd go/src/${goPackagePath}
 
       mkdir -p "$out/bin"
-      install -m 0755 -t "$out/bin" ./dist/artifacts/k3s
+      install -m 0755 -T ./dist/artifacts/k3s${archSuffix} "$out/bin/k3s"
 
       popd
     '';
@@ -203,11 +225,19 @@ stdenv.mkDerivation rec {
   # https://github.com/kubernetes/kubernetes/issues/26093#issuecomment-237202494
   # Note the list in that issue is stale and some aren't relevant for k3s.
   k3sRuntimeDeps = [
-    socat iptables iproute bridge-utils ethtool utillinux ipset conntrack-tools
+    socat
+    iptables
+    iproute
+    bridge-utils
+    ethtool
+    utillinux
+    ipset
+    conntrack-tools
   ];
 
   buildInputs = [
-    k3sBuild makeWrapper
+    k3sBuild
+    makeWrapper
   ] ++ k3sRuntimeDeps;
 
   unpackPhase = "true";

pkgs/applications/networking/cluster/k3s/patches/00-k3s.patch

@@ -55,10 +55,17 @@ index 72d3c07ece..3e5455b262 100755
  echo Building containerd-shim
  make -C ./vendor/github.com/containerd/containerd bin/containerd-shim
 diff --git a/scripts/package-cli b/scripts/package-cli
-index 4c66ce32df..6d1e0c03cb 100755
+index 4c66ce32df..280b428bb8 100755
 --- a/scripts/package-cli
 +++ b/scripts/package-cli
-@@ -55,10 +55,10 @@ LDFLAGS="
+@@ -49,16 +49,16 @@ fi
+ 
+ CMD_NAME=dist/artifacts/k3s${BIN_SUFFIX}
+ 
+-go generate
++CGO_ENABLED=0 env -u GOARCH go generate
+ LDFLAGS="
+     -X github.com/rancher/k3s/pkg/version.Version=$VERSION
      -X github.com/rancher/k3s/pkg/version.GitCommit=${COMMIT:0:8}
      -w -s
  "