Since ABI 23, the core is able to channel T_WOSS, T_WOLI and T_WOSX
error notifications through the offender's observable component if
present.

Convert all SIGDEBUG_xxx cause codes to the new EVL_HMDIAG_xxx naming,
so that we have a single nomenclature for these errors regardless of
whether threads are notified via SIGDEBUG or their observable
component.

The API rev. is bumped to #17 as a result of these changes.

Signed-off-by: Philippe Gerum <rpm@xenomai.org>