diffutils: update to 3.10, drop gcc2 support

fixes #8917

sys-apps/diffutils/patches/diffutils-3.10.patchset

@@ -0,0 +1,19 @@
+From 91479a6afc97d6cf97d18e337ed0a55d21f53738 Mon Sep 17 00:00:00 2001
+From: fbrosson <fbrosson@localhost>
+Date: Sun, 21 Aug 2016 05:35:54 +0000
+Subject: replace /usr/bin/perl by /bin/perl in man/help2man.
+
+
+diff --git a/man/help2man b/man/help2man
+index 7f83481..c48a4dd 100755
+--- a/man/help2man
++++ b/man/help2man
+@@ -1,4 +1,4 @@
+-#!/usr/bin/perl -w
++#!/bin/perl -w
+ 
+ # Generate a short man page from --help and --version output.
+ # Copyright (C) 1997-2005, 2009-2011, 2013, 2015-2023 Free Software Foundation,
+-- 
+2.39.2
+