https://savannah.gnu.org/bugs/?62648#comment22
https://bugs.gentoo.org/880623

# HG changeset patch
# User Rik <rik@octave.org>
# Date 1668451079 28800
#      Mon Nov 14 10:37:59 2022 -0800
# Node ID 67d5b2d119e254efc3d9f2658de47b293ac1f6eb
# Parent  9f4a9dd4a6ee34ddc6e8d0a87d0c703782af7358
doc: Enable building of Qt documentation with Texinfo >= 7.0 (bug #62648)

* mk-qthelp.pl: Update regular expressions that find the start of data in
index.html and Function-index.html to include additional pattern generated by
Texinfo 7.0.

--- a/doc/interpreter/mk-qthelp.pl
+++ b/doc/interpreter/mk-qthelp.pl
@@ -26,8 +26,11 @@ if ($#ARGV != 1)
 open (my $HTML, "<", $htmlfname) or die "Unable to open $htmlfname";
 
 # Skip through preamble of file to find start of list
-while (($_ = <$HTML>) !~ /^<div class="contents">/ ) {;}
-while (($_ = <$HTML>) !~ /^<ul class="no-bullet">/ ) {;}
+while (defined ($_ = <$HTML>) and ! /^<div class="contents">/ ) {;}
+while (defined ($_ = <$HTML>)
+         and ! /^<ul class="(?:no-bullet|toc-numbered-mark)">/ ) {;}
+
+die "index.html: reached EOF without finding data start pattern" if eof ($HTML);
 
 $level = 0;
 while (<$HTML>)
@@ -68,7 +71,11 @@ die "Failed to parse index.html" if ($le
 open ($HTML, "<", $htmlfname) or die "Unable to open $htmlfname";
 
 # Skip through preamble of file to find start of list
-while (($_ = <$HTML>) !~ /^<table class="index-fn/ ) {;}
+while (defined ($_ = <$HTML>)
+         and ! /^<table class="(?:index-fn|fn-entries)/ ) {;}
+
+die "Function-Index.html: reached EOF without finding data start pattern"
+  if eof ($HTML);
 
 while (<$HTML>)
 {