Add two new POWER8 events that are needed for stall analysis

Signed-off-by: Maynard Johnson <maynardj@us.ibm.com>
Converge operf and ocount utility functions

When the ocount tool was developed, a number of utility
functions were needed that were very similar to operf utility
functions, with just minor changes.  The decision was made at
the time to copy these functions into ocount and change them
as needed.  To avoid dual maintenance on very similar functions,
we should converge the two tools to use one common set of utility
functions. The main reason for not doing so in the first place
was to make it easier to review ocount patches and not have to
look at operf changes at the same time.

Signed-off-by: Maynard Johnson <maynardj@us.ibm.com>
configure error message for missing libpfm is not informative enough

On the ppc64 architecture, the libpfm library is used to get perf_events
encodings for events, so the configure script checks for the availability
of that library when building for ppc64. If the library is missing, the
configure error message is:

  checking for perfmon/pfmlib.h... no
  configure: error: pfmlib.h not found; usually provided in papi devel package

However, some newer distros (like Fedora 19) are now delivering separate
packages for libpfm and papi, instead of bundling them together. The patch
provided herein changes the configure message to reflect that change in
packaging.

Signed-off-by: Maynard Johnson <maynardj@us.ibm.com>