toolchain/52171: build.sh seems to require -O option now?

[scole_mail%gmx.com@localhost]

>Number:         52171
>Category:       toolchain
>Synopsis:       build.sh seems to require -O option now?
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 16 17:20:01 +0000 2017
>Originator:     scole_mail
>Release:        current
>Organization:
none
>Environment:
Building current with
NetBSD dstar 7.1.0_PATCH NetBSD 7.1.0_PATCH (GENERIC) #0: Fri Mar 24 12:58:33 PDT 2017  scole@dstar:/home/scole/nbsd/cvs/7_0/obj/sys/arch/i386/compile/GENERIC i386

>Description:
It seems like the default behavior of build.sh changed in the last week or so.

I used to build a release with 
 ./build.sh -j 6 -U  -m ia64 release
which would created obj/ directories by default in the appropriate directories, e.g, 
 src/usr.sbin/mrouted/obj

But this command stopped working.  obj/ directories are still being created but the object files and exe's aren't placed in obj/ anymore, e.g., those files get placed in 
src/usr.sbin/mrouted not src/usr.sbin/mrouted/obj.  This seems to prevent the build from completing.

Adding a -O & -T option (and I guess maybe -M ) allows the build to complete
 ./build.sh -O ../obj -T ../tools -j 6 -U -m ia64

There is a little more info in this thread
http://mail-index.netbsd.org/current-users/2017/04/14/msg031525.html

Not sure if this change was intentional.
>How-To-Repeat:
./build.sh -j 6 -U  -m ia64 release
>Fix: