Better error message when crashing due to nested sETRACE statements.
Fixed a bug that broke compilation on OpenVMS.
Fixed an order-of-execution issues in unittesting/initialization that were made apparent when unittesting on OpenVMS.  skit_sig_init() should have been called before skit_push_tracing_sig_handler(), but wasn't.
Fixed bug in SKIT_ARRAY_ON_STACK that caused compilation problems on OpenVMS.