[index] Fix dangling 'see' references

Also update the automatic check script to prevent
further occurrences.

Author: jensmaurer

source/lex.tex

@@ -357,6 +357,8 @@
 the value of such a code unit can be the same as
 that of a code unit for an element of the basic literal character set.
 \end{note}
+\indextext{character!null}%
+\indextext{wide-character!null}%
 The U+0000 NULL character is encoded as the value \tcode{0}.
 No other element of the translation character set
 is encoded with a code unit of value \tcode{0}.

source/numerics.tex

@@ -10183,7 +10183,7 @@
 \indexlibraryglobal{beta}%
 \indexlibraryglobal{betaf}%
 \indexlibraryglobal{betal}%
-\indextext{Eulerian integral of the first kind|see{\tcode{beta}}}%
+\indextext{Eulerian integral of the first kind|see{beta functions $\mathsf{B}$}}%
 \indextext{beta functions $\mathsf{B}$}%
 \begin{itemdecl}
 double       beta(double x, double y);

source/overloading.tex

@@ -3352,6 +3352,7 @@
 \indextext{postfix ++ and -{-} overloading@postfix \tcode{++} and \tcode{--}!overloading}%
 
 \pnum
+\indextext{overloading!increment operator}%
 An \defnadj{increment}{operator function}
 is a function named \tcode{\keyword{operator}++}.
 If this function is a non-static member function with no non-object parameters, or a non-member
@@ -3408,6 +3409,7 @@
 \end{example}
 
 \pnum
+\indextext{overloading!decrement operator}%
 A \defnadj{decrement}{operator function}
 is a function named \tcode{\keyword{operator}--}
 and is handled analogously to an increment operator function.

tools/check-output.sh

@@ -17,6 +17,22 @@ sed -n '/\.tex/{s/^.*\/\([-a-z0-9]\+\.tex\).*$/\1/;h};
 /Overfull [\\][hv]box\|LaTeX Warning..Reference/{x;p;x;p}' std.log |
     sed '/^.\+\.tex$/{N;s/\n/:/}' | fail || failed=1
 
+# Check for dangling "see" in general index (does not work with formatting)
+grep item < std-generalindex.ind | sed 's/,.*$//;s/\\[sub]*item //' |
+    awk '/^  [^ ]/ { item=$0; print $0 }  /^    [^ ]/ { subitem=$0; print item ", " $0 } /^      [^ ]/ { print item ", " subitem ", " $0 }' |
+    sed 's/^ *//;s/  */ /g' | sort > tmp.txt
+
+grep -o '\\see{[^}]*}' < std-generalindex.ind |
+    sed 's/^\\see{//;s/}$//;s/\\-//' |
+    grep -v "leavevmode\|texttt\|textsc\|kern" |
+    while read see; do
+	if grep -q "$see" tmp.txt; then
+	    :
+	else
+	    grep -n "see{$see}" *.tex | sed 's/$/ is dangling/'
+	fi
+    done | fail || failed=1
+rm -f tmp.txt
 
 # Cross references since the previous standard.
 function indexentries() { sed 's,\\glossaryentry{\(.*\)@.*,\1,' "$1" | LANG=C sort; }