runtime(doc): Add Makefile for the Vim documentation on Windows (#13467)

* Makefile for the Vim documentation on Windows

* Corrected comments

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/doc/vim2html.pl b/runtime/doc/vim2html.pl
index 9066b03..eddfb3a 100644
--- a/runtime/doc/vim2html.pl
+++ b/runtime/doc/vim2html.pl
@@ -6,11 +6,21 @@
 # Sun Feb 24 14:49:17 CET 2002
 
 use strict;
+use warnings;
 use vars qw/%url $date/;
 
 %url = ();
-$date = `date`;
-chop $date;
+# 30.11.23, Restorer:
+# This command does not work in OS Windows.
+# The "date" command in Windows is different from its counterpart in UNIX-like systems.
+# The closest analog is the "date /t" command, but how it would work in UNIX,
+# I don't know. I've corrected it as best I can. I don't know Perl.
+#$date = `date`;
+#chop $date;
+my ($year) = 1900 + (localtime())[5];
+my ($month) = 1 + (localtime())[4];
+my ($day) = (localtime())[3];
+#$date = localtime(); # outputs like this Fri Nov 3 00:56:59 2023
 
 sub maplink
 {
@@ -164,7 +174,7 @@
 	}
 	print OUT<<EOF;
 </pre>
-<p><i>Generated by vim2html on $date</i></p>
+<p><i>Generated by vim2html on $day.$month.$year</i></p>
 </body>
 </html>
 EOF