libcpuid: fix cross compilation to NetBSD

Applies an upstreamed patch which works around a double definition of
popcount64. This change is all needed to cross compile nix to NetBSD, so
we can extend the cross-trunk jobset as well.

pkgs/tools/misc/libcpuid/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, autoreconfHook }:
+{ lib, stdenv, fetchFromGitHub, fetchpatch, autoreconfHook }:
 
 stdenv.mkDerivation rec {
   pname = "libcpuid";
@@ -14,6 +14,12 @@ stdenv.mkDerivation rec {
   patches = [
     # Work around https://github.com/anrieff/libcpuid/pull/102.
     ./stdint.patch
+    # Fixes cross-compilation to NetBSD, remove me for libcpuid > 0.5.1
+    (fetchpatch {
+      name = "use-popcount-from-libc.patch";
+      url = "https://github.com/anrieff/libcpuid/commit/1acaf9980b55ae180cc08db218b9face28202519.patch";
+      sha256 = "0lvsv9baq0sria1f1ncn1b2783js29lfs5fv8milp54pg1wd5b7q";
+    })
   ];
 
   nativeBuildInputs = [ autoreconfHook ];

pkgs/top-level/release-cross.nix

@@ -166,8 +166,7 @@ in
   i686-embedded = mapTestOnCross lib.systems.examples.i686-embedded embedded;
   x86_64-embedded = mapTestOnCross lib.systems.examples.x86_64-embedded embedded;
 
-  # TODO: fix cross compilation of nix{,Unstable} to netbsd and switch to common
-  x86_64-netbsd = mapTestOnCross lib.systems.examples.x86_64-netbsd embedded;
+  x86_64-netbsd = mapTestOnCross lib.systems.examples.x86_64-netbsd common;
 
   # we test `embedded` instead of `linuxCommon` because very few packages
   # successfully cross-compile to Redox so far