dtc: add yaml support and enable tests (NixOS#118700)

pkgs/development/compilers/dtc/default.nix

@@ -1,9 +1,7 @@
 { stdenv, lib, fetchgit, flex, bison, pkg-config, which
-, pythonSupport ? false, python ? null, swig
+, pythonSupport ? false, python, swig, libyaml
 }:
 
-assert pythonSupport -> python != null;
-
 stdenv.mkDerivation rec {
   pname = "dtc";
   version = "1.6.0";
@@ -14,6 +12,7 @@ stdenv.mkDerivation rec {
     sha256 = "0li992wwd7kgy71bikanqky49y4hq3p3vx35p2hvyxy1k0wfy7i8";
   };
 
+  buildInputs = [ libyaml ];
   nativeBuildInputs = [ flex bison pkg-config which ] ++ lib.optionals pythonSupport [ python swig ];
 
   postPatch = ''
@@ -23,10 +22,12 @@ stdenv.mkDerivation rec {
   makeFlags = [ "PYTHON=python" ];
   installFlags = [ "INSTALL=install" "PREFIX=$(out)" "SETUP_PREFIX=$(out)" ];
 
+  doCheck = true;
+
   meta = with lib; {
     description = "Device Tree Compiler";
     homepage = "https://git.kernel.org/cgit/utils/dtc/dtc.git";
-    license = licenses.gpl2; # dtc itself is GPLv2, libfdt is dual GPL/BSD
+    license = licenses.gpl2Plus; # dtc itself is GPLv2, libfdt is dual GPL/BSD
     maintainers = [ maintainers.dezgeg ];
     platforms = platforms.unix;
   };