Treewide: use HTTPS on GNU domains

HTTP -> HTTPS for :
- http://gnu.org/
- http://www.gnu.org/
- http://elpa.gnu.org/
- http://lists.gnu.org/
- http://gcc.gnu.org/
- http://ftp.gnu.org/ (except in fetchurl mirrors)
- http://bugs.gnu.org/

pkgs/tools/text/enscript/default.nix

@@ -35,7 +35,7 @@ stdenv.mkDerivation rec {
 
     license = stdenv.lib.licenses.gpl3Plus;
 
-    homepage = http://www.gnu.org/software/enscript/;
+    homepage = https://www.gnu.org/software/enscript/;
 
     maintainers = [ ];
     platforms = stdenv.lib.platforms.all;