Fix a bug Chris Cambly reported with the timeout code on
AIX. Apparently AIX doesn't permit a forked process to
reference (set) memory in the parent's address space. No
other system seems to object to this practice but it taught
me a lesson!
The fix was to move the call to get the child process start
time directly before calling vfork. This isn't really fair
to the forked process as we start counting time against the
child process that we haven't even forked (we count the
vfork/exec call overhead against the child process).
Tested Rene's test.sh script on Sun, Linux, AIX, and Sgi.