Fix respawn/spawn timers racing ahead under multi-threading

POSIX clock() sums CPU time across every thread in the process, unlike
Windows' clock() which tracks wall-clock milliseconds. With several
worker threads running, respawn/spawn/AI timers based on clock() raced
far ahead of real elapsed time. Switch spawn-timer bookkeeping to
time(NULL)/time_t (seconds) throughout the world server, and add a
portable clock() shim in sockets.h (backed by CLOCK_MONOTONIC,
millisecond resolution) for remaining call sites so CLOCKS_PER_SEC==1000
still holds like it did on Windows.

Also: fix MapDelay/VisualDelay/WorldDelay being passed to usleep() (us)
without converting from their configured milliseconds; fix the shutdown
timer likewise; stop leaking the temporary actor used to run an NPC's
AIP script; fix CleanDrops() skipping the element that shifts into
position after an erase.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Src/World Server/mapfunctions.cpp

@@ -306,11 +306,13 @@ void CMap::UpdateTime( )
 // Clean Drops
 void CMap::CleanDrops( )
 {
-    for(UINT j=0;j<DropsList.size();j++)
+    for(UINT j=0;j<DropsList.size();)
     {
         CDrop* thisdrop = DropsList.at(j);
         if( time(NULL) - thisdrop->droptime >= 50 )
-            DeleteDrop( thisdrop );
+            DeleteDrop( thisdrop ); // erases this element, so don't advance j - the next drop just shifted into position j
+        else
+            j++;
     }
 }
 
@@ -324,19 +326,19 @@ void CMap::RespawnMonster( )
             CSpawnArea* thisspawn = MonsterSpawnList.at(k);
 
             if (thisspawn->respawntime<2)thisspawn->respawntime=2;
-            clock_t rtime = clock() - thisspawn->lastRespawnTime;
-            if((rtime > thisspawn->respawntime*CLOCKS_PER_SEC && thisspawn->amon<thisspawn->max)|| thisspawn->amon<thisspawn->min )
+            time_t rtime = time(NULL) - thisspawn->lastRespawnTime;
+            if((rtime > thisspawn->respawntime && thisspawn->amon<thisspawn->max)|| thisspawn->amon<thisspawn->min )
             {
                 fPoint position = GServer->RandInPoly( thisspawn->points, thisspawn->pcount );
                 AddMonster( thisspawn->montype, position, 0, thisspawn->mobdrop, thisspawn->mapdrop, thisspawn->id );
-                thisspawn->lastRespawnTime = clock();
+                thisspawn->lastRespawnTime = time(NULL);
             }
         }*/
         //PY new spawn code
         for(UINT k=0;k<MonsterSpawnList.size( );k++)
         {
             CSpawnArea* thisspawn = MonsterSpawnList.at(k);
-            clock_t rtime = clock() - thisspawn->lastRespawnTime;
+            time_t rtime = time(NULL) - thisspawn->lastRespawnTime;
             if(thisspawn->limit == 1 && IsNight()) //spawn limit is set to day only
                 continue;
             if(thisspawn->RefVar != 0 && thisspawn->RefVal != 0) //only allow this spawn if the correct ObjVar is set to non zero
@@ -352,18 +354,18 @@ void CMap::RespawnMonster( )
                     // no spawn. this spawn area is inactive
                 break;
                 case 1: //normal spawn
-                    if(rtime > (thisspawn->respawntime * CLOCKS_PER_SEC) && thisspawn->amon < thisspawn->max)
+                    if(rtime > (thisspawn->respawntime) && thisspawn->amon < thisspawn->max)
                     {
                         fPoint position = GServer->RandInCircle( thisspawn->point, thisspawn->radius );
                         UINT aggro = thisspawn->aggressive;
                         AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
-                        thisspawn->lastRespawnTime = clock();
+                        thisspawn->lastRespawnTime = time(NULL);
                         UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                         thisspawn->triggercount = 0;
                     }
                 break;
                 case 2: //normal but fill the spawn
-                    if(rtime > (thisspawn->respawntime * CLOCKS_PER_SEC) && thisspawn->amon < thisspawn->max)
+                    if(rtime > (thisspawn->respawntime) && thisspawn->amon < thisspawn->max)
                     {
                         for(int i=1;i<thisspawn->max;i++)
                         {
@@ -372,6 +374,7 @@ void CMap::RespawnMonster( )
                             AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
                             UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                         }
+                        thisspawn->lastRespawnTime = time(NULL);
                     }
                 break;
                 case 3: //cascade spawn
@@ -380,7 +383,7 @@ void CMap::RespawnMonster( )
                         fPoint position = GServer->RandInCircle( thisspawn->point, thisspawn->radius );
                         UINT aggro = thisspawn->aggressive;
                         AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
-                        thisspawn->lastRespawnTime = clock();
+                        thisspawn->lastRespawnTime = time(NULL);
                         UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                         thisspawn->triggercount = 0;
                     }
@@ -395,12 +398,12 @@ void CMap::RespawnMonster( )
                             AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
                             UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                         }
-                        thisspawn->lastRespawnTime = clock();
+                        thisspawn->lastRespawnTime = time(NULL);
                         thisspawn->triggercount = 0;
                     }
                 break;
                 case 5: //sub spawns. needs to trigger from a specific montype
-                    if(rtime > (thisspawn->respawntime * CLOCKS_PER_SEC) && thisspawn->amon < thisspawn->max)
+                    if(rtime > (thisspawn->respawntime) && thisspawn->amon < thisspawn->max)
                     {
                         //find if any of the trigger mobs exist
                         for(UINT j=0;j<MonsterList.size();j++)
@@ -415,13 +418,13 @@ void CMap::RespawnMonster( )
                                 AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
                                 UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                                 thisspawn->triggercount = 0;
-                                thisspawn->lastRespawnTime = clock();
+                                thisspawn->lastRespawnTime = time(NULL);
                             }
                         }
                     }
                 break;
                 case 6:
-                    if(rtime > (thisspawn->respawntime * CLOCKS_PER_SEC) && thisspawn->amon < thisspawn->max)
+                    if(rtime > (thisspawn->respawntime) && thisspawn->amon < thisspawn->max)
                     {
                         //find if any of the trigger mobs exist
                         for(UINT j=0;j<MonsterList.size();j++)
@@ -438,19 +441,19 @@ void CMap::RespawnMonster( )
                                     AddMonster( thisspawn->montype, position, 0, thisspawn->id, aggro, false, thisspawn->limit );
                                     UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 1); // update the counters
                                 }
-                                thisspawn->lastRespawnTime = clock();
+                                thisspawn->lastRespawnTime = time(NULL);
                                 thisspawn->triggercount = 0;
                             }
                         }
                     }
                 break;
                 case 7: //TDEF spawn. Spawns thisspawn->max monsters one by one using triggercount to track them
-                     if(rtime > (thisspawn->respawntime * CLOCKS_PER_SEC) && thisspawn->triggercount < thisspawn->max)
+                     if(rtime > (thisspawn->respawntime) && thisspawn->triggercount < thisspawn->max)
                     {
                         fPoint position = GServer->RandInCircle( thisspawn->point, thisspawn->radius );
                         AddMonster( thisspawn->montype, position, 0, thisspawn->id, 0, true, 0 );
                         UpdateSpawnCounter( thisspawn->montype, thisspawn->id, 3); // update the counters
-                        thisspawn->lastRespawnTime = clock();
+                        thisspawn->lastRespawnTime = time(NULL);
                     }
                 break;
                 default:
@@ -463,8 +466,8 @@ void CMap::RespawnMonster( )
         for (UINT j = 0; j < MobGroupList.size(); j++)
         {
             CMobGroup* thisgroup = MobGroupList.at(j);
-            clock_t rtime = clock() - thisgroup->lastRespawnTime;
-            if (rtime < thisgroup->respawntime*CLOCKS_PER_SEC || thisgroup->active >= thisgroup->limit)
+            time_t rtime = time(NULL) - thisgroup->lastRespawnTime;
+            if (rtime < thisgroup->respawntime || thisgroup->active >= thisgroup->limit)
                 continue;
             for (UINT k = thisgroup->active; k < thisgroup->limit; k++)
             {