Merge branch 'master' of github.com:cloudius-systems/osv

* 'master' of github.com:cloudius-systems/osv: (30 commits)
  elf: relocate R_X86_64_64 correctly
  sched: make thread stack be controlled by the thread creator
  main: don't destroy DriverFactory for now
  bootfs: disable read01.so temporarily
  mmu: don't map NULL
  libc: fix confstr(NULL, ...)
  elf: fix segfault on unmatched symbol
  mmu: move physical memory map to ffff800000000000
  implement positional I/O (pread/pwrite/preadv/pwritev)
  implement vectored I/O (readv/writev)
  uio-ify the read/write path
  clean up the vnode operation defintion a bit
  import basic uio support code from FreeBSD
  add a real strerror() implementation from musl
  add misc routines from musl
  more stat variants
  add getuid/getgid stubs
  implement lxstat
  implement a real console layer
  simplify the console abstractions
  ...