--- a/build-aux/texinfo.tex	Thu Aug 20 09:09:58 2015 +0900
+++ b/build-aux/texinfo.tex	Wed Aug 26 06:29:21 2015 -0700
@@ -3,7 +3,7 @@
 % Load plain if necessary, i.e., if running under initex.
 \expandafter\ifx\csname fmtname\endcsname\relax\input plain\fi
 %
-\def\texinfoversion{2015-08-24.13}
+\def\texinfoversion{2015-08-25.18}
 %
 % Copyright 1985, 1986, 1988, 1990, 1991, 1992, 1993, 1994, 1995,
 % 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
@@ -346,10 +346,10 @@
     \normalturnoffactive  % \ in index entries must not stay \, e.g., if
                % the page break happens to be in the middle of an example.
                % We don't want .vr (or whatever) entries like this:
-               % \entry{{\tt \indexbackslash }acronym}{32}{\code {\acronym}}
+               % \entry{{\indexbackslash }acronym}{32}{\code {\acronym}}
                % "\acronym" won't work when it's read back in;
                % it needs to be
-               % {\code {{\tt \backslashcurfont }acronym}
+               % {\code {{\backslashcurfont }acronym}
     \shipout\vbox{%
       % Do this early so pdf references go to the beginning of the page.
       \ifpdfmakepagedest \pdfdest name{\the\pageno} xyz\fi
@@ -1053,8 +1053,8 @@
 \newif\iflinks \linkstrue % by default we want the aux files.
 \let\novalidate = \linksfalse
 
-% @setfilename is done at the beginning of every texinfo file.
-% So open here the files we need to have open while reading the input.
+% @setfilename is done at the beginning of every texinfo file.  So open
+% here some of the files we need to have open while reading the input.
 % This makes it possible to make a .fmt file for texinfo.
 \def\setfilename{%
    \iflinks
@@ -1062,7 +1062,6 @@
      % Open the new aux file.  TeX will close it automatically at exit.
      \immediate\openout\auxfile=\jobname.aux
    \fi % \openindices needs to do some work in any case.
-   \openindices
    \let\setfilename=\comment % Ignore extra @setfilename cmds.
    %
    % If texinfo.cnf is present on the system, read it.
@@ -1074,17 +1073,6 @@
    \comment % Ignore the actual filename.
 }
 
-% Called from \setfilename.
-%
-\def\openindices{%
-  \newindex{cp}%
-  \newcodeindex{fn}%
-  \newcodeindex{vr}%
-  \newcodeindex{tp}%
-  \newcodeindex{ky}%
-  \newcodeindex{pg}%
-}
-
 % @bye.
 \outer\def\bye{\pagealignmacro\tracingstats=1\ptexend}
 
@@ -4371,19 +4359,16 @@
 % except not \outer, so it can be used within macros and \if's.
 \edef\newwrite{\makecsname{ptexnewwrite}}
 
-% \newindex {foo} defines an index named foo.
-% It automatically defines \fooindex such that
-% \fooindex ...rest of line... puts an entry in the index foo.
-% It also defines \fooindfile to be the number of the output channel for
-% the file that accumulates this index.  The file's extension is foo.
+% \newindex {foo} defines an index named IX.
+% It automatically defines \IXindex such that
+% \IXindex ...rest of line... puts an entry in the index IX.
+% It also defines \IXindfile to be the number of the output channel for
+% the file that accumulates this index.  The file's extension is IX.
 % The name of an index should be no more than 2 characters long
 % for the sake of vms.
 %
 \def\newindex#1{%
-  \iflinks
-    \expandafter\newwrite \csname#1indfile\endcsname
-    \openout \csname#1indfile\endcsname \jobname.#1 % Open the file
-  \fi
+  \expandafter\chardef\csname#1indfile\endcsname=0
   \expandafter\xdef\csname#1index\endcsname{%     % Define @#1index
     \noexpand\doindex{#1}}
 }
@@ -4397,14 +4382,19 @@
 \def\defcodeindex{\parsearg\newcodeindex}
 %
 \def\newcodeindex#1{%
-  \iflinks
-    \expandafter\newwrite \csname#1indfile\endcsname
-    \openout \csname#1indfile\endcsname \jobname.#1
-  \fi
+  \expandafter\chardef\csname#1indfile\endcsname=0
   \expandafter\xdef\csname#1index\endcsname{%
     \noexpand\docodeindex{#1}}%
 }
 
+% The default indices:
+\newindex{cp}%      concepts,
+\newcodeindex{fn}%  functions,
+\newcodeindex{vr}%  variables,
+\newcodeindex{tp}%  types,
+\newcodeindex{ky}%  keys
+\newcodeindex{pg}%  and programs.
+
 
 % @synindex foo bar    makes index foo feed into index bar.
 % Do this instead of @defindex foo if you don't want it as a separate index.
@@ -4433,24 +4423,19 @@
   \expandafter\xdef\csname#2index\endcsname{\noexpand#1{#3}}%
 }
 
-% Define \doindex, the driver for all \fooindex macros.
+% Define \doindex, the driver for all index macros.
 % Argument #1 is generated by the calling \fooindex macro,
-%  and it is "foo", the name of the index.
-
-% \doindex just uses \parsearg; it calls \doind for the actual work.
-% This is because \doind is more useful to call from other macros.
-
-% There is also \dosubind {index}{topic}{subtopic}
-% which makes an entry in a two-level index such as the operation index.
-
-\def\doindex#1{\edef\indexname{#1}\parsearg\singleindexer}
-\def\singleindexer #1{\doind{\indexname}{#1}}
+% and it the two-letter name of the index.
+
+\def\doindex#1{\edef\indexname{#1}\parsearg\doindexxxx}
+\def\doindexxxx #1{\doind{\indexname}{#1}}
 
 % like the previous two, but they put @code around the argument.
-\def\docodeindex#1{\edef\indexname{#1}\parsearg\singlecodeindexer}
-\def\singlecodeindexer #1{\doind{\indexname}{\code{#1}}}
-
-% Take care of Texinfo commands that can appear in an index entry.
+\def\docodeindex#1{\edef\indexname{#1}\parsearg\docodeindexxxx}
+\def\docodeindexxxx #1{\doind{\indexname}{\code{#1}}}
+
+% Used when writing an index entry out to an index file, to prevent
+% expansion of Texinfo commands that can appear in an index entry.
 % Since there are some commands we want to expand, and others we don't,
 % we have to laboriously prevent expansion for those that we don't.
 %
@@ -4679,6 +4664,9 @@
 % For testing: output @{ and @} in index sort strings as \{ and \}.
 \newif\ifusebracesinindexes
 
+\let\indexlbrace\relax
+\let\indexrbrace\relax
+
 % \indexnofonts is used when outputting the strings to sort the index
 % by, and when constructing control sequence names.  It eliminates all
 % control sequences and just writes whatever the best ASCII sort string
@@ -4704,16 +4692,10 @@
   \def\_{\normalunderscore}%
   \def\-{}% @- shouldn't affect sorting
   %
-  % Unfortunately, texindex is not prepared to handle braces in the
-  % content at all.  So for index sorting, we map @{ and @} to strings
-  % starting with |, since that ASCII character is between ASCII { and }.
-  \ifusebracesinindexes
-    \def\lbracechar{\lbracecmd}%
-    \def\rbracechar{\rbracecmd}%
-  \else
-    \def\lbracechar{|a}%
-    \def\rbracechar{|b}%
-  \fi
+  % Unfortunately, texindex < 6.0 is not prepared to handle braces in the
+  % content at all, so these won't be sorted in ASCII order.
+  \def\lbracechar{{\indexlbrace}}%
+  \def\rbracechar{{\indexrbrace}}%
   \let\{=\lbracechar
   \let\}=\rbracechar
   %
@@ -4795,14 +4777,17 @@
 {\catcode`\`=\active
  \gdef\indexlquoteignore{\let`=\empty}}
 
-\let\indexbackslash=0  %overridden during \printindex.
 \let\SETmarginindex=\relax % put index entries in margin (undocumented)?
 
 % Most index entries go through here, but \dosubind is the general case.
 % #1 is the index name, #2 is the entry text.
 \def\doind#1#2{\dosubind{#1}{#2}{}}
 
-% Workhorse for all \fooindexes.
+% There is also \dosubind {index}{topic}{subtopic}
+% which makes an entry in a two-level index such as the operation index.
+% TODO: Two-level index?  Operation index?
+
+% Workhorse for all indexes.
 % #1 is name of index, #2 is stuff to put there, #3 is subentry --
 % empty if called from \doind, as we usually are (the main exception
 % is with most defuns, which call us directly).
@@ -4810,6 +4795,7 @@
 \def\dosubind#1#2#3{%
   \iflinks
   {%
+    \requireopenindexfile{#1}%
     % Store the main index entry text (including the third arg).
     \toks0 = {#2}%
     % If third arg is present, precede it with a space.
@@ -4825,6 +4811,29 @@
   \fi
 }
 
+% Check if an index file has been opened, and if not, open it.
+\def\requireopenindexfile#1{%
+\ifnum\csname #1indfile\endcsname=0
+  \expandafter\newwrite \csname#1indfile\endcsname
+  \openout \csname#1indfile\endcsname \jobname.#1 % Open the file
+\fi}
+
+% Output \ as {\indexbackslash}, because \ is an escape character in
+% the index files.
+\let\indexbackslash=\relax
+{\catcode`\@=0 \catcode`\\=\active
+  @gdef@useindexbackslash{@def\{{@indexbackslash}}}
+}
+
+% Definition for writing index entry text.
+\def\sortas#1{\eatspaces}%
+
+% Definition for writing index entry sort key.  @sortas{} must occur at
+% the beginning of the index entry, like
+% @cindex @sortas{september} \september
+\def\indexwritesortas#1#2\endofindexentry{#1}
+
+
 % Write the entry in \toks0 to the index file:
 %
 \def\dosubindwrite{%
@@ -4835,14 +4844,15 @@
   %
   % Remember, we are within a group.
   \indexdummies % Must do this here, since \bf, etc expand at this stage
-  \def\backslashcurfont{\indexbackslash}% \indexbackslash isn't defined now
-      % so it will be output as is; and it will print as backslash.
-  %
-  % Process the index entry with all font commands turned off, to
-  % get the string to sort by.
+  \useindexbackslash % \indexbackslash isn't defined now so it will be output 
+                     % as is; and it will print as backslash.
+  % Get the string to sort by, by processing the index entry with all
+  % font commands turned off.
   {\indexnofonts
-   \edef\temp{\the\toks0}% need full expansion
-   \xdef\indexsorttmp{\temp}%
+   \def\endofindexentry{}%
+   \let\sortas=\indexwritesortas
+   \edef\temp{\the\toks0 \noexpand\endofindexentry}%
+   \xdef\indexsortkey{\temp}%
   }%
   %
   % Set up the complete index entry, with both the sort key and
@@ -4852,7 +4862,7 @@
   % sorted result.
   \edef\temp{%
     \write\writeto{%
-      \string\entry{\indexsorttmp}{\noexpand\folio}{\the\toks0}}%
+      \string\entry{\indexsortkey}{\noexpand\folio}{\the\toks0}}%
   }%
   \temp
 }
@@ -5000,7 +5010,9 @@
       % Index files are almost Texinfo source, but we use \ as the escape
       % character.  It would be better to use @, but that's too big a change
       % to make right now.
-      \def\indexbackslash{\backslashcurfont}%
+      \def\indexbackslash{\ttbackslash}%
+      \let\indexlbrace\{   % Likewise, set these sequences for braces
+      \let\indexrbrace\}   % used in the sort key.
       \catcode`\\ = 0
       \escapechar = `\\
       \begindoublecolumns
@@ -5014,9 +5026,6 @@
 % These macros are used by the sorted index file itself.
 % Change them to control the appearance of the index.
 
-{\catcode`\@=0 \catcode`\\=13
-@gdef@usemathbackslash{@def@\{@math{@backslash}}}}
-
 \let\normalhyphen=-
 {\catcode`\/=13 \catcode`\-=13 \catcode`\^=13 \catcode`\~=13 \catcode`\_=13
 \catcode`\|=13 \catcode`\<=13 \catcode`\>=13 \catcode`\+=13 \catcode`\"=13
@@ -5025,7 +5034,8 @@
   % Some changes for non-alphabetic characters.  Using the glyphs from the
   % math fonts looks more consistent than the typewriter font used elsewhere
   % for these characters.
-  \usemathbackslash
+  \def\indexbackslash{\math{\backslash}}%
+  \let\\=\indexbackslash
   %
   % Can't get bold backslash so don't use bold forward slash
   \catcode`\/=13