Revert "Revert "texinfo: 5.2 -> 6.0""

This reverts commit dc74a811291ea5e29e47f7dcc01bdac118f492fb.

This doesn't actually break gcc.

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

···
+{ 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

···
   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 { };
-  texinfo4 = texinfo413;
-  texinfo = texinfo5;
+  texinfo6 = callPackage ../development/tools/misc/texinfo/6.0.nix { };
+  texinfo = texinfo6;
   texinfoInteractive = appendToName "interactive" (
     texinfo.override { interactive = true; }
   );