Merge branch 'staging' into staging-next

This merge actually doesn't seem to be a big rebuild:
     36 x86_64-darwin
    535 x86_64-linux

pkgs/development/libraries/nss/default.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, nspr, perl, zlib, sqlite, fixDarwinDylibNames, buildPackages, ninja }:
+{ stdenv, fetchurl, nspr, perl, zlib, sqlite, darwin, fixDarwinDylibNames, buildPackages, ninja }:
 
 let
   nssPEM = fetchurl {
@@ -19,7 +19,8 @@ in stdenv.mkDerivation rec {
 
   depsBuildBuild = [ buildPackages.stdenv.cc ];
 
-  nativeBuildInputs = [ perl ninja (buildPackages.python2.withPackages (ps: with ps; [ gyp ])) ];
+  nativeBuildInputs = [ perl ninja (buildPackages.python3.withPackages (ps: with ps; [ gyp ])) ]
+    ++ stdenv.lib.optional stdenv.isDarwin darwin.cctools;
 
   buildInputs = [ zlib sqlite ]
     ++ stdenv.lib.optional stdenv.isDarwin fixDarwinDylibNames;
@@ -53,10 +54,6 @@ in stdenv.mkDerivation rec {
 
   patchFlags = [ "-p0" ];
 
-  postPatch = stdenv.lib.optionalString stdenv.isDarwin ''
-    substituteInPlace nss/coreconf/Darwin.mk --replace '@executable_path/$(notdir $@)' "$out/lib/\$(notdir \$@)"
-  '';
-
   outputs = [ "out" "dev" "tools" ];
 
   preConfigure = "cd nss";

pkgs/development/python-modules/gyp/default.nix

@@ -6,13 +6,12 @@
 
 buildPythonPackage {
   pname = "gyp";
-  version = "2015-06-11";
-  disabled = isPy3k;
+  version = "2020-05-12";
 
   src = fetchFromGitiles {
     url = "https://chromium.googlesource.com/external/gyp";
-    rev = "fdc7b812f99e48c00e9a487bd56751bbeae07043";
-    sha256 = "1imgxsl4mr1662vsj2mlnpvvrbz71yk00w8p85vi5bkgmc6awgiz";
+    rev = "caa60026e223fc501e8b337fd5086ece4028b1c6";
+    sha256 = "0r9phq5yrmj968vdvy9vivli35wn1j9a6iwshp69wl7q4p0x8q2b";
   };
 
   prePatch = stdenv.lib.optionals stdenv.isDarwin ''