creating C11 threading library

Since glibc doesn't fully support C11 yet, and thus 'threads.h' isn't
available, I'm implementing a simple wrapper around pthreads to provide the
same functionality.

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
implement C11 threads.h mutexes

Signed-off-by: Steven Noonan <steven@uplinklabs.net>
implement C11 threads.h condition variables

Signed-off-by: Steven Noonan <steven@uplinklabs.net>