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/compilers/gcc/6/default.nix

@@ -355,7 +355,7 @@ stdenv.mkDerivation ({
     then "install-strip"
     else "install";
 
-  # http://gcc.gnu.org/install/specific.html#x86-64-x-solaris210
+  # https://gcc.gnu.org/install/specific.html#x86-64-x-solaris210
   ${if hostPlatform.system == "x86_64-solaris" then "CC" else null} = "gcc -m64";
 
   # Setting $CPATH and $LIBRARY_PATH to make sure both `gcc' and `xgcc' find the
@@ -416,7 +416,7 @@ stdenv.mkDerivation ({
   inherit (stdenv) is64bit;
 
   meta = {
-    homepage = http://gcc.gnu.org/;
+    homepage = https://gcc.gnu.org/;
     license = stdenv.lib.licenses.gpl3Plus;  # runtime support libraries are typically LGPLv3+
     description = "GNU Compiler Collection, version ${version}"
       + (if stripped then "" else " (with debugging info)");