Revert "texinfo: 5.2 -> 6.0"

This reverts commit b1ed04ad1d. It breaks gcc:

http://hydra.nixos.org/build/24651204

pkgs/development/tools/misc/texinfo/6.0.nix

@@ -1,44 +0,0 @@
-{ stdenv, fetchurl, ncurses, perl, xz, interactive ? false }:
-
-stdenv.mkDerivation rec {
-  name = "texinfo-6.0";
-
-  src = fetchurl {
-    url = "mirror://gnu/texinfo/${name}.tar.xz";
-    sha256 = "1r3i6jyynn6ab45fxw5bms8mflk9ry4qpj6gqyry72vfd5c47fhi";
-  };
-
-  buildInputs = [ perl xz ]
-    ++ stdenv.lib.optional interactive ncurses;
-
-  preInstall = ''
-    installFlags="TEXMF=$out/texmf-dist";
-    installTargets="install install-tex";
-  '';
-
-  doCheck = !stdenv.isDarwin;
-
-  meta = {
-    homepage = "http://www.gnu.org/software/texinfo/";
-    description = "The GNU documentation system";
-    license = stdenv.lib.licenses.gpl3Plus;
-    platforms = stdenv.lib.platforms.all;
-
-    longDescription = ''
-      Texinfo is the official documentation format of the GNU project.
-      It was invented by Richard Stallman and Bob Chassell many years
-      ago, loosely based on Brian Reid's Scribe and other formatting
-      languages of the time.  It is used by many non-GNU projects as
-      well.
-
-      Texinfo uses a single source file to produce output in a number
-      of formats, both online and printed (dvi, html, info, pdf, xml,
-      etc.).  This means that instead of writing different documents
-      for online information and another for a printed manual, you
-      need write only one document.  And when the work is revised, you
-      need revise only that one document.  The Texinfo system is
-      well-integrated with GNU Emacs.
-    '';
-    branch = "5.2";
-  };
-}

pkgs/top-level/all-packages.nix

@@ -5811,10 +5811,9 @@ let
   teensy-loader = callPackage ../development/tools/misc/teensy { };
 
   texinfo413 = callPackage ../development/tools/misc/texinfo/4.13a.nix { };
-  texinfo4 = texinfo413;
   texinfo5 = callPackage ../development/tools/misc/texinfo/5.2.nix { };
-  texinfo6 = callPackage ../development/tools/misc/texinfo/6.0.nix { };
-  texinfo = texinfo6;
+  texinfo4 = texinfo413;
+  texinfo = texinfo5;
   texinfoInteractive = appendToName "interactive" (
     texinfo.override { interactive = true; }
   );