pkg/47525: fetch from sourceforge fails if user sets own FTPUSERAGENT

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>Number:         47525
>Category:       pkg
>Synopsis:       fetch from sourceforge fails if user sets own FTPUSERAGENT
>Confidential:   no
>Severity:       non-critical
>Priority:       high
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Feb 02 22:10:01 +0000 2013
>Originator:     Izumi Tsutsui
>Release:        NetBSD 6.0
>Organization:
>Environment:
System: NetBSD i386 6.0 + pkgsrc HEAD
Architecture: i386
Machine: i386
>Description:
sourceforge download sites seem to check client's useragent value
and change behavior of download pages so if a user sets own FTPUSERAGENT
("Mozilla/5.0" etc.) for ftp(1) fetching from sourceforge fails.

It was once fixed in pkgsrc/mk/fetch/fetch.mk rev 1.57:
http://mail-index.netbsd.org/pkgsrc-changes/2012/12/14/msg081842.html
but in rev 1.58 FTPUSERAGENT variable is passed again on make fetch:
http://cvsweb.netbsd.org/bsdweb.cgi/pkgsrc/mk/fetch/fetch.mk.diff?r1=1.57&r2=1.58

>How-To-Repeat:
% cd pkgsrc/x11/mlterm ; env FTPUSERAGENT="Mozilla/5.0" make fetch

>Fix:
Use pkgsrc own variable to override ftp(1)'s FTPUSERAGENT in fetch.mk?
(I'm not sure which package has sites "broken without FTPUSERAGENT" though)