Modules TSC: Add mutex for server.lruclock.

Only useful for when no atomic builtins are available.

src/server.c

@@ -1432,6 +1432,7 @@ void initServerConfig(void) {
     server.lua_time_limit = LUA_SCRIPT_TIME_LIMIT;
 
     unsigned int lruclock = getLRUClock();
+    pthread_mutex_init(&server.lruclock_mutex,NULL);
     atomicSet(server.lruclock,lruclock);
     resetServerSaveParams();
 

src/server.h

@@ -861,6 +861,7 @@ struct redisServer {
     dict *orig_commands;        /* Command table before command renaming. */
     aeEventLoop *el;
     unsigned int lruclock;      /* Clock for LRU eviction */
+    pthread_mutex_t lruclock_mutex;
     int shutdown_asap;          /* SHUTDOWN needed ASAP */
     int activerehashing;        /* Incremental rehash in serverCron() */
     int active_defrag_running;  /* Active defragmentation running (holds current scan aggressiveness) */