bin/43517: patch(1) does not fail when used with unknown option

[lacombar%gmail.com@localhost]

>Number:         43517
>Category:       bin
>Synopsis:       patch(1) does not fail when used with unknown option
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jun 25 16:25:00 +0000 2010
>Originator:     Arnaud Lacombe
>Release:        netbsd-5
>Organization:
n/a
>Environment:
NetBSD bla 5.99.25 NetBSD 5.99.25 (GENERIC) #0: Tue Apr 27 22:29:06 EDT 2010  
al@bla:/misc/build/obj/sys/arch/i386/compile/GENERIC i386
>Description:
When used with unknown options, patch(1) returns a success, however, patch is 
not applied.
>How-To-Repeat:
% echo foo > orig
% echo bar > changed
% diff -u orig changed > change  
% patch --no-backup-if-mismatch < change
patch: unknown option -- no-backup-if-mismatch
usage: patch [-bCcEeflNnRstuv] [-B backup-prefix] [-D symbol] [-d directory]
             [-F max-fuzz] [-i patchfile] [-o out-file] [-p strip-count]
             [-r rej-name] [-V t | nil | never] [-x number] [-z backup-ext]
             [--posix] [origfile [patchfile]]
       patch <patchfile
% echo $?
0
% cat orig 
foo
% patch < change                       
Hmm...  Looks like a unified diff to me...
The text leading up to this was:
--------------------------
|--- orig       2010-06-25 12:13:51.000000000 -0400
|+++ changed    2010-06-25 12:14:02.000000000 -0400
--------------------------
Patching file orig using Plan A...
Hunk #1 succeeded at 1.
done
% echo $?
0
% cat orig
bar

>Fix:
should be trivial :)