* Acknowledge receive of page-fault signal with ack_signal,
but restart thread execution separately
* use kill_signal_context when disolving a pager_object to prevent race
* Remove bureaucracy in form of Thread_event and Signal_ack_handler
* remove dead code in riscv, namely Thread_base definition
* translation_table_insertions function for ARM drops out,
which was overcautious
'block_for_signal' and 'pending_signal' now set pending flag in signal context
in order to determine pending signal. The context list is also used by the
'Signal_receiver' during destruction.
Fixes#1738
There were two bugs. First, the caller of Kernel::await_signal wasn't
re-activated for scheduling. Second, the caller did not memorize that he
doesn't wait on a receiver anymore which had bad side effects on further
signal handling.
Fix#1459
This patch changes the top-level directory layout as a preparatory
step for improving the tools for managing 3rd-party source codes.
The rationale is described in the issue referenced below.
Issue #1082
