There are binaries for v.build, the sub-program that v.support
calls to build topology and the one that gives the core dump,
at:
ftp://moon.cecer.army.mil/pub/grass/incoming/Vector
You should be able to download v.build.sun4 and copy it to
$GISBASE/etc/v.build, then run v.support OK. If that doesn't
work, then you've probably discovered a new bug which should be
reported to grassbugs@diego.cecer.army.mil.
- Bill