Added original SDK code for Alien Swarm.

public/vallocator.cpp

@@ -0,0 +1,36 @@
+//========= Copyright <20> 1996-2005, Valve Corporation, All rights reserved. ============//
+//
+// Purpose: 
+//
+// $NoKeywords: $
+//
+//=============================================================================//
+
+#if !defined(_STATIC_LINKED) || defined(_SHARED_LIB)
+
+#include <malloc.h>
+#include "vallocator.h"
+#include "basetypes.h"
+
+// memdbgon must be the last include file in a .cpp file!!!
+#include "tier0/memdbgon.h"
+
+VStdAllocator g_StdAllocator;
+
+void* VStdAllocator::Alloc(unsigned long size)
+{
+	if(size)
+	{
+		void *ret = malloc(size);
+		return ret;
+	}
+	else
+		return 0;
+}
+
+void VStdAllocator::Free(void *ptr)
+{
+	free(ptr);
+}
+
+#endif // !_STATIC_LINKED || _SHARED_LIB