open, _open, stat, unlink and rmdir forwarded the result of their sceKernel
twin, so a failure returned 0x8002xxxx instead of -1 and errno was never set
to the guest error. They now return -1 with errno set to the code carried by
the sce error, and report a null pointer as EFAULT and an empty path as
ENOENT.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>