Enable or disable following of symbolic links.
Some physical filesystems and archives contain files that are just pointers to other files. On the physical filesystem, opening such a link will (transparently) open the file that is pointed to.
By default, PhysicsFS will check if a file is really a symlink during open calls and fail if it is. Otherwise, the link could take you outside the write and search paths, and compromise security.
If you want to take that risk, call this function with a non-zero parameter. Note that this is more for sandboxing a program's scripting language, in case untrusted scripts try to compromise the system. Generally speaking, a user could very well have a legitimate reason to set up a symlink, so unless you feel there's a specific danger in allowing them, you should permit them.
Symlinks are only explicitly checked when dealing with filenames in platform-independent notation. That is, when setting up your search and write paths, etc, symlinks are never checked for.
Symbolic link permission can be enabled or disabled at any time after you've called (init), and is disabled by default.