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/networking/mailutils/default.nix

@@ -118,7 +118,7 @@ stdenv.mkDerivation rec {
 
     maintainers = with maintainers; [ orivej vrthra ];
 
-    homepage = http://www.gnu.org/software/mailutils/;
+    homepage = https://www.gnu.org/software/mailutils/;
 
     # Some of the dependencies fail to build on {cyg,dar}win.
     platforms = platforms.gnu ++ platforms.linux;