bin/41781: vi regex regression matching dollar signs

[bad%bsd.de@localhost]

>Number:         41781
>Category:       bin
>Synopsis:       the pattern /\$/ doesn't match a dollar sign anymore by default
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jul 25 15:50:00 +0000 2009
>Originator:     Christoph Badura
>Release:        NetBSD 5.0_STABLE
>Organization:
netbsd bozotic software test labs
        
>Environment:
        
        
System: NetBSD sanctioned-parts-list 5.0_STABLE NetBSD 5.0_STABLE (pe1400) #0: 
Sun Jul 12 17:58:26 UTC 2009 bad@arbitrary:/m/src/sys/arch/i386/compile/pe1400 
i386
Architecture: i386
Machine: i386
>Description:
        
The new vi in NetBSD 5 does not allow to match a literal $ by default.
This used to work until e.g. NetBSD 3.x.

mrg@ provided the hint that the behaviour changes with setting "extended"
mode for regular expressions on.

However, the NetBSD 3.x vi does allow escaping a dollar sign with a backslash
and matching a literal dollar sign with either setting of "extended".

>How-To-Repeat:
        
$ cat >zorch <<\ETX
a
b\$c
d
ETX
$ env EXINIT=":se noext" vi -c ':/\\\$/p' zorch
$ env EXINIT=":se ext" vi -c ':/\\\$/p' zorch

>Fix:
unknown
        

>Unformatted:
 NetBSD 5.0_STABLE as of 2009-07-02