https://github.com/gwsw/less/pull/567
From c02f7554a1e5685e4332fb6857e95761953c8db4 Mon Sep 17 00:00:00 2001
From: Mark Nudelman <markn@greenwoodsoftware.com>
Date: Mon, 9 Sep 2024 14:48:10 -0700
Subject: [PATCH] Allow SOURCE_DATE_EPOCH to override timestamps in generated
 files.

Related to #567.

diff --git a/mkhelp.pl b/mkhelp.pl
index e93535b..452d9a0 100755
--- a/mkhelp.pl
+++ b/mkhelp.pl
@@ -7,7 +7,7 @@ use strict;
 # whose content is the input to this script.
 
 {
-    my ($sec,$min,$hour,$mday,$mon,$year) = gmtime();
+    my ($sec,$min,$hour,$mday,$mon,$year) = gmtime($ENV{SOURCE_DATE_EPOCH} // time());
     printf "/* This file was generated by mkhelp.pl from less.hlp at %d:%02d on %d/%d/%d */\n",
         $hour, $min, $year+1900, $mon+1, $mday;
     print "#include \"less.h\"\n";