Merge pull request #84415 from matthewbauer/mb-cross-fixes-april2020

Cross compilation fixes [april 2020]

pkgs/os-specific/linux/plymouth/default.nix

@@ -1,5 +1,5 @@
 { stdenv, fetchurl, autoreconfHook, pkgconfig, libxslt, docbook_xsl
-, gtk3, udev, systemd
+, gtk3, udev, systemd, lib
 }:
 
 stdenv.mkDerivation rec {
@@ -44,6 +44,7 @@ stdenv.mkDerivation rec {
     "--enable-pango"
     "--enable-gdm-transition"
     "--enable-gtk"
+    "ac_cv_path_SYSTEMD_ASK_PASSWORD_AGENT=${lib.getBin systemd}/bin/systemd-tty-ask-password-agent"
   ];
 
   configurePlatforms = [ "host" ];