sdate: move autoreconfHook to nativeBuildInputs, minor cleanups

pkgs/tools/misc/sdate/default.nix

···
 { lib, stdenv, fetchFromGitHub, autoreconfHook }:
+
 stdenv.mkDerivation rec {
   pname = "sdate";
   version = "0.7";
···
     hash = "sha256-jkwe+bSBa0p1Xzfetsdpw0RYw/gSRxnY2jBOzC5HtJ8=";
   };
 
-  buildInputs = [ autoreconfHook ];
+  nativeBuildInputs = [ autoreconfHook ];
 
-  meta = {
+  meta = with lib; {
     homepage = "https://www.df7cb.de/projects/sdate";
     description = "Eternal september version of the date program";
-    license = lib.licenses.gpl2Plus;
-    maintainers = with lib.maintainers; [ edef ];
-    platforms = lib.platforms.all;
+    license = licenses.gpl2Plus;
+    maintainers = with maintainers; [ edef ];
+    platforms = platforms.all;
   };
 }