lightdm: use regular gettext to fix build

`glib` gettext is deprecated and currently broken.
This fixes the build by using regular gettext instead.

pkgs/applications/display-managers/lightdm/default.nix

@@ -8,8 +8,8 @@
   plymouth,
   pam,
   pkg-config,
-  autoconf,
-  automake,
+  autoreconfHook,
+  gettext,
   libtool,
   libxcb,
   glib,
@@ -50,8 +50,8 @@ stdenv.mkDerivation rec {
   };
 
   nativeBuildInputs = [
-    autoconf
-    automake
+    autoreconfHook
+    gettext
     yelp-tools
     yelp-xsl
     gobject-introspection
@@ -88,6 +88,9 @@ stdenv.mkDerivation rec {
     (replaceVars ./fix-paths.patch {
       plymouth = "${plymouth}/bin/plymouth";
     })
+
+    # glib gettext is deprecated and broken, so use regular gettext instead
+    ./use-regular-gettext.patch
   ];
 
   dontWrapQtApps = true;

pkgs/applications/display-managers/lightdm/use-regular-gettext.patch

@@ -0,0 +1,13 @@
+diff --git a/configure.ac b/configure.ac
+index 6f2e706f..6307dd59 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -195,6 +195,8 @@ dnl Internationalization
+ dnl ###########################################################################
+ 
+ IT_PROG_INTLTOOL(0.35.0)
++AM_GNU_GETTEXT([external])
++AM_GNU_GETTEXT_VERSION([0.21])
+ AC_SUBST(GETTEXT_PACKAGE, lightdm)
+ AC_DEFINE_UNQUOTED(GETTEXT_PACKAGE, "$GETTEXT_PACKAGE", Gettext package)
+