REPARTITION LIBC FUNCTIONALITY

```
Description: There are many things implemented within the kernel (for example
under sched/pthread) that probably should be migrated in the
C library where it belongs.

I would really like to see a little flavor of a micro-kernel
at the OS interface: I would like to see more primitive OS
system calls with more higher level logic in the C library.

One awkward thing is the incompatibility of KERNEL vs FLAT
builds: In the kernel build, it would be nice to move many
of the thread-specific data items out of the TCB and into
the process address environment where they belong. It is
difficult to make this compatible with the FLAT build,
however.
Status: Open
Priority: Low

NOTE: The NXFFS file system has its own TODO list at nuttx/fs/nxffs/README.txt
```