0.9.5.58:

0.9.5.58:
  * nasty interrupt bug:
    1) sigalrm handler is deferred
    2) later it's run via sigtrap handler
    3) handler does pa_alloc while sigtrap is blocked
    4) gc is needed and another sigtrap is triggered by 3)
    5) stupid Linux kernel sees that sigtrap is blocked and invokes the
       default handler (see http://groups.google.com/group/fa.linux.kernel/browse_frm/thread/455401a6837c72bf/865ea792a236299c)
    6) coredump
    Adding SA_NODEFER to sigaction is enough for sane systems to fix this.
    Not for buggy Linux 2.6. A compile time test was added for
    sigaction and SA_NODEFER allowing the runtime to work around this
    bug (see interrupt.c).
  * added missing sigemptysets