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/gdbm/default.nix

@@ -60,7 +60,7 @@ stdenv.mkDerivation rec {
          package also provides traditional dbm and ndbm interfaces.
       '';
 
-    homepage = http://www.gnu.org/software/gdbm/;
+    homepage = https://www.gnu.org/software/gdbm/;
     license = licenses.gpl3Plus;
     platforms = platforms.all;
     maintainers = [ maintainers.vrthra ];