Sync build-aux/update-copyright from Gnulib

* build-aux/update-copyright: Copy from Gnulib.
This should simplify this year's updating.

Author: eggert

build-aux/update-copyright

@@ -138,7 +138,7 @@
 eval 'exec perl -wSx -0777 -pi "$0" "$@"'
      if 0;
 
-my $VERSION = '2024-07-04.10:56'; # UTC
+my $VERSION = '2025-01-01.07:36'; # UTC
 # The definition above must lie within the first 8 lines in order
 # for the Emacs time-stamp write hook (at end) to update it.
 # If you change this file with Emacs, please let the write hook
@@ -235,7 +235,7 @@ while (/(^|\n)(.{0,$prefix_max})$copyright_re/cg)
             else
               {
                 my $ndash = ($ARGV =~ /\.tex(i(nfo)?)?$/ ? "--"
-                             : $ARGV =~ /\.(\d[a-z]*|man)$/ ? "\\(en"
+                             : $ARGV =~ /\.(\d[a-z]*|man)(\.in)?$/ && $ARGV !~ /ChangeLog\./ ? "\\(en"
                              : "-");
 
                 $stmt =~