[ISSUE] File size of games not shown

[rickgaiser]

As reported in #300 loading time was problematic. A workaround has been found (see 63367d2) by temporarily not checking file sizes.

To fix this issue, readdir has to also return the stuct stat, just like the old fileXio functions did. This is possible within the standards. Changes have to be made to:

• newlib: to modify the definition of the structs (like this)
• ps2sdk/libc: to fill the new structs (like this)
• OPL: to use the size returned by readdir (like this)