I confess I don't even know what questions to ask in my current
situation.

For the past two days I've been struggling to define my problem,
and I've finally discovered something I just don't understand.

I've discovered that doing a 'build.sh build' fails in two
completely different ways, depending on whether I try it from
an xterm window or from a regular (pseudo-terminal) console.

If I start an X session and do:
# cd /usr/src
# sh build.sh build
then the build fails in the same spot every time in
/usr/src/gnu/dist/texinfo during the 'configure' phase when
checking if integer-division-by-zero raises a SIGFPE signal.
The test run by 'configure' just hangs forever, consuming all
the CPU cycles until I kill the test.

I can duplicate the problem just by doing this from an xterm:
# cd /usr/src/gnu/dis/texinfo
# ./configure [this hangs forever]

On the other hand, if do the build.sh build from a regular
pseudo-terminal, I see the same failure that was discussed
in the -current mail-list today and was supposed to be fixed
by Christos's commit to share/mk/bsd.own.mk, but wasn't fixed.

Any ideas?