added barriers, started working on libraries

engine/filesystem_pak.cpp

@@ -82,7 +82,7 @@ public:
 			return;
 		delete pHandle;
 	}
+	virtual CUtlBuffer<unsigned char> Read( IFileHandle *pFile ) override { return NULL; }; 
 };
 
-CPAKFileSystem g_pakFileSystem;
-IFileSystem *filesystem_pak = &g_pakFileSystem;
+EXPOSE_FILESYSTEM(CPAKFileSystem, "pakfs");