Some public header files were missing 'extern "C"' C++ guards,
and couldn't be used by C++ applications. Add the missing guards.
Fixes: c5b7197f662e ("telemetry: move some functions to metrics library")
Cc: stable@dpdk.org
Signed-off-by: Brian Dooley <brian.dooley@intel.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Tyler Retzlaff <roretzla@linux.microsoft.com>
4e90b3a3d6