* spu/jsre.h: Add defines for new assist calls.
* spu/chdir.c: New file, support chdir via assist call.
* spu/chmod.c: New file, support chmod via assist call.
* spu/chown.c: New file, support chown via assist call.
* spu/fchdir.c: New file, support fchdir via assist call.
* spu/fchmod.c: New file, support fchmod via assist call.
* spu/fchown.c: New file, support fchown via assist call.
* spu/lchown.c: New file, support lchown via assist call.
* spu/mkdir.c: New file, support mkdir via assist call.
* spu/mknod.c: New file, support mknod via assist call.
* spu/rmdir.c: New file, support rmdir via assist call.
* spu/Makefile.in: Add new files.
