What steps will reproduce the problem?
Call heap-profiler_unittest with the arguments 1 -2 (one iteration, 2 fork()ed children).

What is the expected output? What do you see instead?
Instead of running the test, the program crashes with a std::bad_alloc exception.
This is caused by unconditionally passing the number-of-threads-argument (0 or positive
for threads, negative for fork()s) in RunManyThreads(), thus allocating an array of
pthread_t of size -2.
Depending on the sign of the thread number argument either RunManyThreads or fork()
should be called.

What version of the product are you using? On what operating system?
Git HEAD, Ubuntu 13.04, 3.8.0-19-generic

Please provide any additional information below.
Patch attached.

Best regards,
Hannes Weisbach