[meson] use a more high-level name and description for the userspace-RCU option

meson.build

@@ -19,7 +19,7 @@ run_target('iwyu',
 		   command: 'tools/check-iwyu')
 
 conf_data = configuration_data()
-conf_data.set('EMPER_LIBURCU', get_option('liburcu'))
+conf_data.set('EMPER_LIBURCU', get_option('userspace-rcu'))
 conf_data.set('EMPER_WORKER_SLEEP', get_option('worker_sleep'))
 conf_data.set('EMPER_LOCKED_WS_QUEUE', get_option('locked_ws_queue'))
 conf_data.set('EMPER_OVERFLOW_QUEUE', get_option('overflow_queue'))

meson_options.txt

 option(
-  'liburcu',
+  'userspace-rcu',
   type: 'boolean',
   value: true,
-  description: 'Register worker threads for the default userspace RCU flavor',
+  description: 'Allow EMPER fibers to use userspace RCU',
 )
 option(
   'worker_sleep',