autoconf: Fix bug when autom4te updates too quickly

https://github.com/libsdl-org/autoconf/commit/3a9802d60156809c139e9b4620bf04917e143ee2

From 3a9802d60156809c139e9b4620bf04917e143ee2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andreas=20K=2E=20H=C3=BCttel?= <[EMAIL REDACTED]>
Date: Tue, 31 Aug 2021 17:01:47 -0700
Subject: [PATCH] Fix bug when autom4te updates too quickly

Use stat from Time::HiRes (instead of File::stat).

Problem reported by Ionen Wolkens <https://bugs.gentoo.org/782985>.
---
 lib/Autom4te/FileUtils.pm | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/lib/Autom4te/FileUtils.pm b/lib/Autom4te/FileUtils.pm
index a182031b..27a5fd91 100644
--- a/lib/Autom4te/FileUtils.pm
+++ b/lib/Autom4te/FileUtils.pm
@@ -34,12 +34,12 @@ This perl module provides various general purpose file handling functions.
 
 =cut
 
-use 5.006;
+use 5.008;
 use strict;
 use warnings FATAL => 'all';
 
 use Exporter;
-use File::stat;
+use Time::HiRes qw(stat);
 use IO::File;
 
 use Autom4te::Channels;
@@ -115,10 +115,11 @@ sub mtime ($)
   return 0
     if $file eq '-' || ! -f $file;
 
-  my $stat = stat ($file)
+  my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
+    $atime,$mtime,$ctime,$blksize,$blocks) = stat ($file)
     or fatal "cannot stat $file: $!";
 
-  return $stat->mtime;
+  return $mtime;
 }