pkg/60574: transmission-daemon etc. abort on invalid toupper(3) call

>Number:         60574
>Category:       pkg
>Synopsis:       transmission-daemon etc. abort on invalid toupper(3) call
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Aug 11 04:30:00 +0000 2026
>Originator:     Wolfgang Corcoran-Mathe
>Release:        NetBSD 11.0 / transmission 4.06
>Organization:
>Environment:
NetBSD xanthus.sigwinch.xyz 11.0 NetBSD 11.0 (GENERIC) #0: Thu Jul 30 15:23:12 UTC 2026  [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
transmission-daemon and transmission-show 4.0.6 both abort and dump core with "ctype(3) toupper: invalid input: -61" when parsing certain torrent seed files.  The message is always the same, i.e. the erroneous toupper input is always -61. This problem began occurring after I upgraded the system to NetBSD 11.0: the problem files worked with transmission 4.0.6 on NetBSD 10.1.
>How-To-Repeat:
Invoke transmission-show on a problematic torrent file, or try to add it to the daemon's active torrents using 'transmission-remote -a <file>'. Unfortunately, I have not been to pin down which seeds cause this behavior.
>Fix: