Add mod security

Due to compatibility concerns, this is temporarily disabled.

src/filesys.h

@@ -103,13 +103,17 @@ std::string RemoveLastPathComponent(const std::string &path,
 // this does not resolve symlinks and check for existence of directories.
 std::string RemoveRelativePathComponents(std::string path);
 
-// Return the filename from a path or the entire path if no directory delimiter
-// is found.
+// Returns the absolute path for the passed path, with "." and ".." path
+// components and symlinks removed.  Returns "" on error.
+std::string AbsolutePath(const std::string &path);
+
+// Returns the filename from a path or the entire path if no directory
+// delimiter is found.
 const char *GetFilenameFromPath(const char *path);
 
 bool safeWriteToFile(const std::string &path, const std::string &content);
 
-}//fs
+} // namespace fs
 
 #endif