Implementing libc

- Makefile for libc (static libc for now)
- Modifications to libc to make it compile without any kernel functions
- Removed libc functions that are too hard to implement properly for the
  current system
Kconfig changes

- refactoring libkern opt for size
- qemu guest support knob
Porting libc and working on sbin compilation
Working on pthread mutex

Cleaning up old ulocks code and bringin up C thread and pthread
locks.

Still missing signals which is going to be a problem.
Adding static man pages
This is not needed in repo
Fix thread ctors & dtors and atomic_cmpxchg retval
Developing signal userspace code
Proper psignal()
Developing system initialization and signals

- Implementing signal handling into kernel
- Don't try to handle signals in libc
- Fix crt1 argument hadling, I have an idea now how to pass args and env
More signal handling functionality in kernel
Remove _syscalldef.h and mode struct types under corresponding libc header files
More proper wait to use signals in mutex code
Signal handling should start if thread is waiting for the signal
Implementing signal syscalls
Priv to set signal actions
Split libc functions to one function per file

This split will make linking easier and binaries smaller because
linker can skip unneeded object files.
Developing signal handling
Split kill lib functions to separate files
Doxygenizing stdio.h