OpenBSD pcap_open_offline(3) does not set file descriptor.

Index: t/16-setnonblock.t
--- t/16-setnonblock.t.orig
+++ t/16-setnonblock.t
@@ -5,6 +5,7 @@ use Test::More;
 use Net::Pcap;
 use lib 't';
 use Utils;
+use Errno 'EBADF';
 
 plan skip_all => "pcap_setnonblock() and pcap_getnonblock() are not available"
   unless is_available('pcap_setnonblock');
@@ -87,9 +88,11 @@ SKIP: {
 }
 
 # Testing getnonblock()
+$! = EBADF;
+my $error = "$!";
 eval { $r = Net::Pcap::getnonblock($pcap, \$err) };
 is( $@,   '', "getnonblock()" );
-is( $err, '', " - err must be null" );
-is( $r,    0, " - state must be 0 for savefile" );
+is( $err, "F_GETFL: $error", " - err must be EBADF" );
+is( $r,   -1, " - state must be -1 for savefile" );
 
 Net::Pcap::close($pcap);