diff --git a/ChangeLog b/ChangeLog
index 72e8eef..f45022e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2024-07-21  Bruno Haible  <bruno@clisp.org>
+
+	build: Fix use of perl on Guix, FreeBSD, NetBSD.
+	* doc/help2man: Search for perl in $PATH.
+
 2024-07-21  Bruno Haible  <bruno@clisp.org>
 
 	build: Fix "make maintainer-clean".
diff --git a/doc/help2man b/doc/help2man
index 7734d23..5226bd4 100755
--- a/doc/help2man
+++ b/doc/help2man
@@ -1,7 +1,7 @@
-#!/usr/bin/perl -w
+#!/usr/bin/env perl
 
 # Generate a short man page from --help and --version output.
-# Copyright © 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+# Copyright © 1997-2000, 2024 Free Software Foundation, Inc.
 
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -21,6 +21,7 @@
 
 use 5.004;
 use strict;
+use warnings;
 use Getopt::Long;
 use Text::Tabs qw(expand);
 use POSIX qw(strftime setlocale LC_TIME);
@@ -30,7 +31,7 @@ my $this_version = '1.23';
 my $version_info = <<EOT;
 GNU $this_program $this_version
 
-Copyright (C) 1997, 1998, 1999, 2000 Free Software Foundation, Inc.
+Copyright (C) 1997-2000, 2024 Free Software Foundation, Inc.
 This is free software; see the source for copying conditions.  There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.