7f00133337
Previously: host_redox_stubs returned ENOSYS for all syscalls except close/munmap/get_euid/ruid/egid/rgid — silent failures when IOMMU code was tested on the host. Now (host only): - open/read/write/close → real libc file I/O - mmap → real libc memory allocation (MAP_ANON|MAP_PRIVATE) - munmap → real libc munmap - clock_gettime → real libc CLOCK_REALTIME - fstat → real libc fstat - fsync/fdatasync/ftruncate → real libc ops - getpid/getuid/geteuid/getgid/getegid → real libc - strerror → real libc strerror (not hardcoded message) - 12 remaining unsupported ops: ENOSYS with same semantics (dup, signals, waitpid, namespaces — not needed for IOMMU tests)