bin/46782: date -r (8) returns incorrect values

[mac%SS.Culver.Net@localhost]

>Number:         46782
>Category:       bin
>Synopsis:       date -r overflows
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Aug 07 22:35:00 +0000 2012
>Originator:     mac%SS.Culver.Net@localhost
>Release:        NetBSD 5.1_RC3
>Organization:
        
>Environment:
System: NetBSD SS.Culver.Net 5.1_RC3 NetBSD 5.1_RC3 (GENERIC) #0: Sat Jun 12 
20:26:01 UTC 2010 
builds%b8.netbsd.org@localhost:/home/builds/ab/netbsd-5-1-RC3/amd64/201006130031Z-obj/home/builds/ab/netbsd-5-1-RC3/src/sys/arch/amd64/compile/GENERIC
 amd64
Architecture: x86_64
Machine: amd64
>Description:
        date -r overflows
>How-To-Repeat:
        date -r `echo '2^31-1'|bc` ; date -r `echo '2^31'|bc`
>Fix:
        

>Unformatted: