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/gnused/default.nix

@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
   PERL = if stdenv.hostPlatform == stdenv.buildPlatform then null else "missing";
 
   meta = {
-    homepage = http://www.gnu.org/software/sed/;
+    homepage = https://www.gnu.org/software/sed/;
     description = "GNU sed, a batch stream editor";
 
     longDescription = ''