Drop "Copyright abandonded" header

Add CC0 as the license. SPDX does not have a "public domain" tag, but CC0 is
more or less equivalent. We should have *some* header to avoid doubts in the
future.

diff --git a/tools/check-includes.pl b/tools/check-includes.pl
index 6aae7c15348be7e2d6c1458234757c24089e00d3..c8bfcba8c0f067fdd06eaaae69bffbbe55321146 100755 (executable)
--- a/tools/check-includes.pl
+++ b/tools/check-includes.pl
@@ -1,7 +1,7 @@
+# SPDX-License-Identifier: CC0-1.0
 #!/usr/bin/env perl
 #
 # checkincludes: Find files included more than once in (other) files.
-# Copyright abandoned, 2000, Niels Kristian Bech Jensen <nkbj@image.dk>.
 
 foreach $file (@ARGV) {
        open(FILE, $file) or die "Cannot open $file: $!.\n";