Anybody else seen this? It's _extremely_ rare. I've seen it exactly twice,
both times running the same program - a test/unit test suite using
Tk::TestRunner. In the meantime I've run the program successfully dozens of
times. This last time it happened when I ran the program immediately after
issuing an `export -n ...' command.

tim: ~/vslick/rvg/test> export -n debug_prim=
tim: ~/vslick/rvg/test> ruby W3C*
/home/software/ruby-1.8.2//lib/ruby/1.8/tk/variable.rb:321: [BUG]
Segmentation fault
ruby 1.8.2 (2004-12-25) [i686-linux]

Aborted