Eventfds are pollable (no iow thread is blocked reading from the IO object)
contrary to waitfds.
And using pipes seams also rather excessive especially since we ensure
that only a single notification is written before it is consumed.

This makes the code of the IO-based sleep strategies easier and I would
expect also faster.

Introduce AbstractIoSleepStrategy holding most of the code needed for
a sleep strategy using an IO object fur suspension/notification.

This changes are used in future patches to implement more IO-based
sleep strategies.

[gitlab-ci] Bump debian-testing-dev image to 1.24

See merge request i4/manycore/emper!410

use liburing 2.2 wrap file provided via meson wrapdb

See merge request i4/manycore/emper!405

fix Future cancellation when using SINGLE_URING

See merge request i4/manycore/emper!407

When using the SINGLE_URING configuration the Future semaphore is used
to ensure that a forgotten Future is dropped after it is prepared and
not needed anymore.

Using the future after signaling its semaphore and thus allowing its
concurrent destruction is obviously broken.

Signal the semaphore after all preparation work is done.

Fixes: 9c0f2143

Fixes: 3fb3892b

[Semaphore] make default constructor more explicit

See merge request i4/manycore/emper!408

The CancelFutureTest fails for libc++ because it uses two
emper::Semaphores to coordinate the involved fibers.

Using gcc and stdlibc++ the default constructor initialized the
semaphore count to 0.

The default constructor using clang and libc++ does not initialize the
semaphore count member and thus causing the CancelFutureTest to misbehave.

Add the Big Fancy Pulser 9000 (BFP 9K) evaluation

See merge request !397

[README] Fibirl uses spawn/sync as keywords (and no longer fork/join)

See merge request i4/manycore/emper!403

[io/Stats] For AlarmFutures (TIMEOUT) expect them to return ETIME

See merge request i4/manycore/emper!402

[Makefile] Add asan(-test) targets

See merge request i4/manycore/emper!398

LTO

See merge request i4/manycore/emper!401

This prevents a linker error because of undefined symbols when LTO is
used.

[Runtime] Switch logging of env var handling from DBG() to LOGI()

See merge request i4/manycore/emper!400

Also use std::boolalpha to print ture/false.

[SpuriousFutex2Semaphore] Add missing emper-config.h include

See merge request i4/manycore/emper!399

Fixes: f4e72a97 ("[iwyu] Fix includes as per iwyu 0.18")

[ContextManager] Remove the put/get free context cycle

See merge request i4/manycore/emper!396

The put/get free context cycle in ContextManager::start() (if
continuation stealing is enabled) became unnecessary with
c66551bf ("[Context] Use 'jmp' instead of 'ret' to kickoff the
context").

Fix ContextManager with MemoryManager

See merge request i4/manycore/emper!395

Even though the MemoryManager is enabled for the ContextManager per
default, it never was actually used due a logic bug. Squash that bug!

In case a Context has been retrieved from the MemoryManager, without
it malloced, then we need to re-initialze some of the Context's values
before we can use the Context.

Kickoff context using 'jmp' instead of 'ret'

See merge request i4/manycore/emper!394

My system running 5.15.43 also returns ECANCELED.