texinfo: move ncurses support into texinfoInteractive

This, for example, drops the stdenv dependency on ncurses.

pkgs/development/tools/misc/texinfo/5.2.nix

@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, ncurses, perl, xz }:
+{ stdenv, fetchurl, ncurses, perl, xz, interactive ? false }:
 
 stdenv.mkDerivation rec {
   name = "texinfo-5.2";
@@ -8,7 +8,8 @@ stdenv.mkDerivation rec {
     sha256 = "1njfwh2z34r2c4r0iqa7v24wmjzvsfyz4vplzry8ln3479lfywal";
   };
 
-  buildInputs = [ ncurses perl xz ];
+  buildInputs = [ perl xz ]
+    ++ stdenv.lib.optional interactive ncurses;
 
   preInstall = ''
     installFlags="TEXMF=$out/texmf-dist";

pkgs/top-level/all-packages.nix

@@ -3914,6 +3914,9 @@ let
   texinfo5 = callPackage ../development/tools/misc/texinfo/5.2.nix { };
   texinfo4 = texinfo413;
   texinfo = texinfo5;
+  texinfoInteractive = appendToName "interactive" (
+    texinfo.override { interactive = true; }
+  );
 
   texi2html = callPackage ../development/tools/misc/texi2html { };