vchoi_fork

[svn-r11259] Purpose:
Bug fix

Description:
ph5diff had been hanging in Tflops.  Found out that vsnprintf ph5diff
uses was a local coded that did not limit printing according to the size
argument.  That resulted in buffer overflow and other problems.

Solution:
Added some sort of size checking in the home-grown vsnprintf and
had ph5diff checked for error return of vsnprintf.  Leon also
revamped the ph5diff manager's way of handling communications with
the workers.  That eliminated all but the last case of hanging.

Platforms tested:
Tflops.

Misc. update: