Added most recent version of unmodified HL2 SDK for Episode 1 engine

dlls/terrainmodmgr.h

@@ -0,0 +1,21 @@
+//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//=============================================================================//
+
+#ifndef TERRAINMODMGR_H
+#define TERRAINMODMGR_H
+#ifdef _WIN32
+#pragma once
+#endif
+
+#include "vector.h"
+#include "terrainmod.h"
+
+// Apply a terrain mod.
+// The mod is applied on the server, and sent to all clients so they can apply it.
+void TerrainMod_Add( TerrainModType type, const CTerrainModParams &params );
+
+#endif // TERRAINMODMGR_H