add futex2 flavor

bench/emper.py

@@ -147,6 +147,9 @@ FLAVORS: Flavors = {
         'meson_options': '-Dworker_wakeup_strategy=all',
         'patches': ['fix_free_vs_delete.patch', 'wakeup-condvar.patch'],
     },
+    'wakeup-futex2': {
+        'meson_options': '-Dwakeup_semaphore_implementation=futex2'
+    },
     'wakeup-futex': {
         'meson_options': '-Dwakeup_semaphore_implementation=futex'
     },