From http://www.jwz.org/xscreensaver/xscreensaver-5.17.tar.gz

[xscreensaver] / OSX / icmp-warning.pl

diff --git a/OSX/icmp-warning.pl b/OSX/icmp-warning.pl
new file mode 100755 (executable)
index 0000000..ac76fdc
--- /dev/null
+++ b/OSX/icmp-warning.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/perl -w
+# Copyright © 2012 Jamie Zawinski <jwz@jwz.org>
+#
+# Permission to use, copy, modify, distribute, and sell this software and its
+# documentation for any purpose is hereby granted without fee, provided that
+# the above copyright notice appear in all copies and that both that
+# copyright notice and this permission notice appear in supporting
+# documentation.  No representations are made about the suitability of this
+# software for any purpose.  It is provided "as is" without express or 
+# implied warranty.
+#
+# Created: 20-Jun-2012.
+
+require 5;
+use diagnostics;
+use strict;
+
+my $progname = $0; $progname =~ s@.*/@@g;
+my $version = q{ $Revision: 1.1 $ }; $version =~ s/^[^\d]+([\d.]+).*/$1/;
+
+my $verbose = 0;
+
+sub sanity_check() {
+
+  my $fail = '';
+  my $d1 = $ENV{SDK_DIR} || '';
+  my $d2 = '/usr/include/netinet/';
+  foreach my $f ('ip.h', 'in_systm.h', 'ip_icmp.h', 'ip_var.h', 'udp.h') {
+    $fail .= "\tsudo ln -s $d2$f $d1$d2\n"
+      unless (-f "$d1$d2$f");
+  }
+
+  exit (0) unless $fail;
+
+  print STDERR "ERROR:\t" . join(' ',  # "\n\t",
+     'The "Sonar" module won\'t build properly unless you repair your',
+     'SDK first.  With some versions of Xcode, the ICMP header files',
+     'are present in the iPhone Simulator SDK but are missing from',
+     'the "real device" SDK.  You can fix it by doing this:') .
+       "\n\n$fail\n";
+  exit (1);
+}
+
+if ($#ARGV >= 0) {
+  print STDERR "usage: $progname\n";
+  exit 1;
+}
+
+sanity_check();