Add $! to errors, use script basename.

Reviewed-by: NRichard Levitte <levitte@openssl.org>

crypto/objects/objxref.pl

@@ -7,7 +7,7 @@ my %oid_tbl;
 
 my ($mac_file, $xref_file) = @ARGV;
 
-open(IN, $mac_file) || die "Can't open $mac_file";
+open(IN, $mac_file) || die "Can't open $mac_file, $!\n";
 
 # Read in OID nid values for a lookup table.
 
@@ -19,7 +19,7 @@ while (<IN>)
 	}
 close IN;
 
-open(IN, $xref_file) || die "Can't open $xref_file";
+open(IN, $xref_file) || die "Can't open $xref_file, $!\n";
 
 my $ln = 1;
 
@@ -57,8 +57,7 @@ my @srt2 = sort
 	} @xrkeys;
 
 my $pname = $0;
-
-$pname =~ s|^.[^/]/||;
+$pname =~ s|.*/||;
 
 print <<EOF;
 /* AUTOGENERATED BY $pname, DO NOT EDIT */
@@ -111,6 +110,6 @@ sub check_oid
 	my ($chk) = @_;
 	if (!exists $oid_tbl{$chk})
 		{
-		die "Not Found \"$chk\"\n";
+		die "Can't find \"$chk\", $!\n";
 		}
 	}