In this homework, you'll use a real tool on Linux to find problems in
multi-threaded code. The tool is called helgrind (available as part of the
valgrind suite of debugging tools).

See http://valgrind.org/docs/manual/hg-manual.htm for details about the tool,
including how to download and install it (if it's not already on your Linux
system).

You'll then look at a number of multi-threaded C programs to see how you can
use the tool to debug problematic threaded code.

First things first: download and install valgrind and the related helgrind
tool. 

Then, type "make" to build all the different programs. Examine the Makefile
for more details on how that works.

Then, you have a few different C programs to look at:

- main-race.c
  A simple race condition

- main-deadlock.c
  A simple deadlock

- main-deadlock-global.c
  A solution to the deadlock problem

- main-signal.c
  A simple child/parent signaling example

- main-signal-cv.c
  A more efficient signaling via condition variables

- mythreads.h
  Header file with wrappers to make code check errors and be more readable

With these programs, you can now answer the questions in the textbook.