anchor.diff: -{ stdenv, fetchurl, pkgconfig, meson, ninja, libpthreadstubs, libpciaccess, valgrind-light }:
  +{ stdenv, lib, fetchurl, pkgconfig, meson, ninja, libpthreadstubs, libpciaccess
  +, withValgrind ? valgrind-light.meta.available, valgrind-light
  +}:
   
   stdenv.mkDerivation rec {
     pname = "libdrm";
  
positive.code:   outputs = [ "out" "dev" "bin" ];
  
    nativeBuildInputs = [ pkgconfig meson ninja ];
    buildInputs = [ libpthreadstubs libpciaccess valgrind-light ];
  
    patches = [ ./cross-build-nm-path.patch ];
  
  
negative.code:     homepage = https://dri.freedesktop.org/libdrm/;
      description = "Library for accessing the kernel's Direct Rendering Manager";
      license = "bsd";
      platforms = lib.platforms.unix;
    };
  }
  