Add keyvalue to disable item dropping

twhl-community/halflife-op4-updated#72

dlls/basemonster.h

@@ -46,6 +46,7 @@ class CBaseMonster : public CBaseToggle
 		float				m_flWaitFinished;// if we're told to wait, this is the time that the wait will be over.
 		float				m_flMoveWaitFinished;
 		float				m_flLastYawTime;
+		bool				m_AllowItemDropping = true;
 
 		Activity			m_Activity;// what the monster is doing (animation)
 		Activity			m_IdealActivity;// monster should switch to this activity
@@ -339,11 +340,14 @@ class CBaseMonster : public CBaseToggle
 	BOOL ExitScriptedSequence( );
 	BOOL CineCleanup( );
 
-	CBaseEntity* DropItem ( const char *pszItemName, const Vector &vecPos, const Vector &vecAng );// drop an item.
+	/**
+	*	@brief Drop an item.
+	*	Will return @c nullptr if item dropping is disabled for this NPC.
+	*/
+	CBaseEntity* DropItem(const char* pszItemName, const Vector& vecPos, const Vector& vecAng);
+
 	void StartPatrol( CBaseEntity *path );
 
-	CBaseEntity* DropItem ( char *pszItemName, const Vector &vecPos, const Vector &vecAng );// drop an item.
-
 	//LRC
 	float	CalcRatio( CBaseEntity *pLocus )
 	{

dlls/monsters.cpp

@@ -3016,6 +3016,10 @@ void CBaseMonster :: KeyValue( KeyValueData *pkvd )
 		m_iPlayerReact = atoi( pkvd->szValue );
 		pkvd->fHandled = TRUE;
 	}
+	else if (FStrEq(pkvd->szKeyName, "allow_item_dropping"))
+	{
+		m_AllowItemDropping = atoi(pkvd->szValue) != 0;
+	}
 	else
 	{
 		CBaseToggle::KeyValue( pkvd );
@@ -3478,9 +3482,14 @@ CBaseEntity* CBaseMonster :: DropItem ( const char *pszItemName, const Vector &v
 	if ( !pszItemName )
 	{
 		ALERT ( at_console, "DropItem() - No item name!\n" );
-		return NULL;
+		return nullptr;
 	}
-
+
+	if (!m_AllowItemDropping)
+	{
+		return nullptr;
+	}
+
 	CBaseEntity *pItem = CBaseEntity::Create( pszItemName, vecPos, vecAng, edict() );
 
 	if ( pItem )