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/groff/default.nix

@@ -107,7 +107,7 @@ stdenv.mkDerivation rec {
   '';
 
   meta = with stdenv.lib; {
-    homepage = http://www.gnu.org/software/groff/;
+    homepage = https://www.gnu.org/software/groff/;
     description = "GNU Troff, a typesetting package that reads plain text and produces formatted output";
     license = licenses.gpl3Plus;
     platforms = platforms.all;