examples / ParallelJIT

Hi!

This example currently uses pthread.h, but will be good idea to
convert it to C++11 thread and synchronization objects.

I think will be good idea if person who knows LLVM and C++1 better
then me will take care about conversion.

Eugene.

Definitely. Also, https://llvm.org/bugs/show_bug.cgi?id=25224 might
be worth looking while there.