[meson] set check_anywhere_queue_while_steal automatic

We introduced the check_anywhere_queue_while_steal configuration as an optimization to get the IO completions reaped by the completer faster into the normal WSQs. But now the emper has configurations where we don't use a completer thus making this optimization useless or rather harmful.

By default automatically decide the value of check_anywhere_queue_while_steal based on the value of io_completer_behavior.

meson.build

@@ -44,7 +44,6 @@ conf_data.set('EMPER_WORKER_WAKEUP_STRATEGY', get_option('worker_wakeup_strategy
 conf_data.set('EMPER_LOCKED_WS_QUEUE', get_option('locked_ws_queue'))
 conf_data.set('EMPER_LOCKED_MPSC_QUEUE', get_option('locked_mpsc_queue'))
 conf_data.set('EMPER_OVERFLOW_QUEUE', get_option('overflow_queue'))
-conf_data.set('EMPER_CHECK_ANYWHERE_QUEUE_WHILE_STEALING', get_option('check_anywhere_queue_while_stealing'))
 conf_data.set('EMPER_STATS', get_option('stats'))
 conf_data.set('EMPER_OVERFLOW_QUEUE', get_option('overflow_queue'))
 conf_data.set('EMPER_BLOCKED_CONTEXT_SET', get_option('blocked_context_set'))
@@ -133,6 +132,17 @@ endif
 
 conf_data.set('EMPER_IO_COMPLETER_BEHAVIOR', io_completer_behavior)
 
+# Decide on scheduling optimization introduced because of the completer
+# moving work to the AnywhereQueue.
+check_anywhere_queue_while_stealing = get_option('check_anywhere_queue_while_stealing')
+if check_anywhere_queue_while_stealing == 'auto'
+	conf_data.set('EMPER_CHECK_ANYWHERE_QUEUE_WHILE_STEALING',
+	              io_completer_behavior == 'schedule')
+else
+	conf_data.set('EMPER_CHECK_ANYWHERE_QUEUE_WHILE_STEALING',
+	              check_anywhere_queue_while_stealing == 'true')
+endif
+
 # check io meson options consistency
 if get_option('io_single_uring')
 	if not (io_completer_behavior == 'schedule')