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/development/libraries/gettext/default.nix

@@ -75,7 +75,7 @@ stdenv.mkDerivation rec {
       GNU packages produce multi-lingual messages.
     '';
 
-    homepage = http://www.gnu.org/software/gettext/;
+    homepage = https://www.gnu.org/software/gettext/;
 
     maintainers = with maintainers; [ zimbatm vrthra ];
     license = licenses.gpl2Plus;