POSIX requires that setitimer, getitimer, and alarm work on a per-process
basis.  Currently, Linux implements these for individual threads.  This patch
fixes these semantics for the ITIMER_PROF timer (which generates SIGPROF) and
the ITIMER_VIRTUAL timer (which generates SIGVTALRM), making them shared by
all threads in a process (thread group).  This patch should be applied after
the one that fixes ITIMER_REAL.

The essential machinery for these timers is tied into the new posix-timers
code for process CPU clocks and timers.  This patch requires the cputimers
patch and its dependencies.
Signed-off-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>