Merge master into staging-next

pkgs/development/compilers/cmdstan/default.nix

@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchurl, python, runtimeShell }:
+{ lib, stdenv, fetchurl, python3, runtimeShell }:
 
 stdenv.mkDerivation {
   name = "cmdstan-2.17.1";
@@ -12,7 +12,7 @@ stdenv.mkDerivation {
   enableParallelBuilding = true;
 
   doCheck = true;
-  checkInputs = [ python ];
+  checkInputs = [ python3 ];
   checkPhase = "python ./runCmdStanTests.py src/test/interface"; # see #5368
 
   installPhase = ''

pkgs/development/compilers/dtc/default.nix

@@ -1,7 +1,9 @@
 { stdenv, lib, fetchgit, flex, bison, pkg-config, which
-, pythonSupport ? false, python, swig
+, pythonSupport ? false, python ? null, swig
 }:
 
+assert pythonSupport -> python != null;
+
 stdenv.mkDerivation rec {
   pname = "dtc";
   version = "1.6.0";