libc: Add inotify stubs

This patch adds inotify API stubs. The lack of inotify prevents booting
an application under OSv completely.

  https://github.com/cloudius-systems/capstan/issues/65



Signed-off-by: Pekka Enberg <penberg@cloudius-systems.com>
Signed-off-by: Avi Kivity <avi@cloudius-systems.com>