* spu/dirfuncs.c: New file, holds the opendir, closedir, readdir,
rewinddir, seekdir and telldir implementations. These are
grouped in one file so that we do not need a separate file for
the struct dirent and DIR allocation code.
* spu/jsre.h: Add JSRE_OPENDIR and other dir opcodes.
* spu/Makefile.in: Add dirfuncs.o.
